Exhibit E3b to the record of the Forum: the light in the lane at night

The document in full

Open the original PDF

Page 1

Exhibit E3b to the DCF record: the light in the lane at night, CLAG’s technical note (25 September 2026) The applicant counts two public benefits from the library windows on Christ’s Lane: light on the lane at night and natural surveillance of it. Its own documents contradict both. The applicant assures the residents opposite that the same light will not disturb them, and no measurement on the register supports the claim or the assurance. The windows are “positioned to avoid overlooking” the building opposite, every window sits above the eye height of a person in the lane, the views from the lane are “looking diagonally upwards”, and the Master calls the library “essentially a private space”. Light from windows high in a narrow lane goes mostly sideways rather than down, to the building opposite, and little of it reaches the pavement. The Council’s own environmental health officer treats the same light as a disturbance to the residents, to be assessed and controlled by condition. Every applicant statement on overlooking and light rests on a drawing of the design before the September 2025 amendment, which the Council’s own officer records as superseded. CLAG promised this note at the Development Control Forum of 29 July 2026 (the DCF record, entry 4.22), and files it as an exhibit to that record. CLAG asks the Council to require the lighting assessment its own officer requires before any weight is given to the light claim, and to state by Tuesday 29 September 2026 that it will require it before the report is written. Submitted for the public register of application 26/02109/FUL, to be recorded under the heading above and displayed on the day it reaches the Council, Friday 25 September 2026, beside CLAG’s DCF record: the Council’s notice of 19 August 2026 states that views are “published onto the website promptly” (document 9499001), and the applicant’s letters of 5 and 27 August 2026 were displayed within a day (documents 9486713 and 9506331). Application 26/02109/FUL: Christ’s College Library, St Andrew’s Street, Cambridge. Christ’s Lane Action Group (CLAG). Filed as an exhibit to CLAG’s DCF record of 25 September 2026, under the undertaking recorded at its entry 4.22. It states every point it relies on, so that it stands on its own. Exhibit D5, the applicant’s section across the lane (Design and Access Statement part 2, document 9423961, page 44) with a line added at eye height, is at Appendix A; it is the section figure CLAG’s other papers refer to. To: planning@greatercambridgeplanning.org and PlanningComments@greatercambridgeplanning.org, for the attention of Dominic Bush (case officer); copy Vanessa Blane (Senior Planning Lawyer, 3C Shared Services); copy Stephen Kelly (Joint Director of Planning and Economic Development, Greater Cambridge Shared Planning); copy legal@3csharedservices.org (the 3C Shared Legal Practice, the address the Council has stated as its accepted point of service). From: Christ’s Lane Action Group (residents@christs-lane.com). Filed Friday 25 September 2026. Every quotation is verbatim from the document cited, and documents are cited by their numbers on the register of this application unless another register is named. Christ’s College is the applicant. Every level and dimension is the applicant’s; where CLAG derives a figure from the applicant’s dimensions, it says so. The Development Control Forum of 29 July 2026 is “the DCF”, and CLAG’s transcript extract of it, to which this note is an exhibit, is “the DCF record”, cited by entry number. Terms in quotation marks are defined where they first appear.

Page 2

Contents 1.

The applicant claims a public benefit from light the windows will put into the lane at night and assures the residents opposite that the same light will not disturb them, and no measurement on the register supports either

2.

The natural surveillance the applicant counts as a public benefit is contradicted by its own design: windows above eye height positioned to avoid overlooking, views “diagonally upwards”, and a library the Master calls “essentially a private space”

3.

Light from windows high in a narrow lane goes mostly sideways to the building opposite and little reaches the pavement, and the Council’s own environmental health officer treats the same light as a disturbance to be controlled, so it cannot be counted as a benefit

4.

Every applicant statement on overlooking and light rests on a drawing of the design before the September 2025 amendment, which the Council’s own officer records as superseded, so the assessment must be made again for the building applied for and consulted on again

5.

The report counts no benefit from light or surveillance, records that the applicant’s assessment is of a superseded design, and requires the lighting assessment before it is written, or it weighs benefits the register does not show

1. The applicant claims a public benefit from light the windows will put into the lane at night and assures the residents opposite that the same light will not disturb them, and no measurement on the register supports either HE6(4) of the National Planning Policy Framework of 17 August 2026 (“the NPPF”) weighs harm to a designated heritage asset against “any public benefits resulting from the proposal”. The applicant claims, in three places on the register, that light from the library windows will light Christ’s Lane at night and make it safer. In the chapter of its Planning Statement addressed to the residents opposite, the applicant states that the same light will not disturb them. No document on the register measures the light, so neither statement rests on evidence, and the assurance to the residents is the applicant’s own evidence against the benefit. If the windows will put enough light into the lane to serve as a safety benefit, the assurance to the residents does not hold, and the effect of that light on them must be assessed as the Council’s own environmental health officer requires (section 3). If the windows will not, the claimed benefit does not exist and nothing enters the balance under HE6(4) on its account. On either footing the case officer’s report to committee on this application (“the report”) cannot carry both statements, and it can carry neither as a fact without the measurement. 1.

The claim is made in three places: (a)

the Planning Statement (Turley, document 9423963; “the Planning Statement”), paragraph 8.13: “public benefits will accrue from its design and high quality materials, the incorporation of the bench and the ability for glimpse views in and natural surveillance and diffused lighting out of the new library, with benefits in terms of safety (and perception) of those using Christ’s Lane.”;

Page 3

(b)

the applicant’s presenter at the DCF (the DCF record, entry 4.20): “it is a blank ugly wall and the next one will be beautiful and varied with different windows, more light pouring into the lane. So it will be much more attractive.”;

(c)

the Bursar’s letter to all City Councillors (document 9465769): “Light from the windows of the new Library will cast light on Christ’s Lane in the dark, improving the sense of security for pedestrians.”

2.

The same Planning Statement, in the chapter addressed to the residents of Bradwell’s Court, states at paragraph 7.74: “The new windows are not considered to be large enough or in locations where diffused light from within would cause disturbance to the residents on the opposite of Christ’s Lane, particularly in a city centre location where night-time lighting levels are relatively high.”

3.

The Design and Access Statement (Grafton Architects, document 9423961; “the Design and Access Statement”) states beside its section across the lane (part 2, page 44): “As the Library will be opened 24 hours a day, the presence of light on the Lane from the windows at night will create an added sense of security. Light will be controlled so that residents are not disturbed at night.” The same page states: “Library windows facing Christs Lane are positioned opposite the blank walls or small windows of the commercial floor of the building on the opposite side.” (sic).

4.

The residents’ windows face the library windows across the lane at the same levels, and the applicant dimensions the lane at 5.665 m between the two buildings (page 44; Exhibit D5). Light from a library window reaches a resident’s window across the lane on a level path of that length. The pavement lies across the lane and below the windows, so light from the same window reaches it on a slanting path, down as well as across, which is longer than 5.665 m and meets the pavement at a slant. Light too weak to disturb the residents at their windows arrives at the pavement weaker still. The applicant adds that the lane is already lit at night to levels that are “relatively high” and that the light from the windows “will be controlled”.

The report must record that the claim and the assurance rest on the same light and that no document on the register measures it. If the Council requires the lighting assessment at section 3 before any weight is given to the claim, the claim and the assurance are tested together. If the Council does not, the claim rests on no evidence on the file, and the applicant’s own paragraph 7.74 stands against it. A report that carries it as a fact misleads members on a matter of fact (R (Mansell) v Tonbridge and Malling BC [2017] EWCA Civ 1314, [2019] PTSR 1452 at [42]).

2. The natural surveillance the applicant counts as a public benefit is contradicted by its own design: windows above eye height positioned to avoid overlooking, views “diagonally upwards”, and a library the Master calls “essentially a private space” The applicant counts “natural surveillance” from the library windows as a public benefit for the safety of those using Christ’s Lane (section 1, item 1(a)). Its own documents describe a building designed so that its users do not overlook the other side of the lane and are not seen from it. The windows are “positioned to avoid overlooking” the building opposite; every window sits above the eye height of a person in the lane; the views from the lane are “looking diagonally upwards”, so that students’ privacy is not compromised; and the Master describes the library as “essentially a private space”. Of the Local Plan’s own natural surveillance and active frontage criteria, the applicant’s Planning Statement says they “are not considered particularly relevant”. A building designed not to overlook the lane’s other side and not to be seen into from the lane does not provide natural surveillance of the lane.

Page 4

If the report gives natural surveillance no weight under HE6(4) and records that the applicant does not claim that the building meets Policy 56(d) or (e), the balance carries no benefit the applicant’s own documents contradict. If the report counts natural surveillance as a public benefit, or describes the frontage as active at the level of the lane, it adopts a description the applicant’s own section and words contradict and misleads members on a matter of fact (Mansell at [42]). 1.

Policy 56 of the Cambridge Local Plan 2018 (“Policy 56”) asks that proposals “d. ensure that buildings are orientated to provide natural surveillance;” and “e. create active edges on to public space by locating appropriate uses, as well as entrances and windows of habitable rooms next to the street;”. The applicant’s Planning Statement answers at paragraph 7.39: “Whilst strands d. and e. which consider natural surveillance and active frontages are not considered particularly relevant, the increased openings into the library and likely greater use of the gateway into Bath Court will improve the feeling of natural surveillance for users of Christ’s Lane particularly at night.” The applicant does not claim that the building meets either criterion. What it claims is a feeling, and at paragraph 8.13 that feeling becomes “natural surveillance” among the public benefits.

2.

The section across the lane (Design and Access Statement part 2, page 44; Exhibit D5) reproduces drawing 004700 at revision P01, dated 23 May 2025. On it the lane is at level 10.335 and the library’s first floor at 12.160, 1.825 m above the lane; the parapet is dimensioned 12.495 m above the lane; and the lane is 5.665 m wide between the two buildings. The applicant states the levels and the width; CLAG derives the 1.825 m from them.

3.

The lane windows are labelled A, B and C. Window C, the lowest, is drawn with its sill at the First Floor level, 1.825 m above the lane; window B between the Second and Third Floor levels; window A between the Third and Fourth Floor levels. The lift lobby section on the same page draws two further windows, E and D, at the lift lobby levels 13.900 and 16.945. CLAG adds to the drawing a line at 1.6 m above the lane, the eye height of a standing adult, as a general figure (Exhibit D5). The line lies below the sill of every window on the frontage. At that level a person in the lane faces brick along the whole frontage, from the lane to the parapet 12.495 m above it.

4.

The applicant’s own words describe a design that avoids overlooking and being seen into. The caption to the section reads: “Library Windows on Christ’s Lane positioned to avoid overlooking of Bradwells Court on the opposite side of the Lane” (part 2, page 44). The text beside it: “Library windows facing Christs Lane are positioned opposite the blank walls or small windows of the commercial floor of the building on the opposite side.” (sic) and “Views into the library will be possible from Christ Lane, looking diagonally upwards, in a manner which will not compromise the students privacy.” (sic). Of the elevation: “New windows are introduced at upper levels in the wall” (part 2, page 30).

5.

The Master, summing up for the applicant at the DCF (the DCF record, entry 4.24): “it is a library and a library is essentially a private space. We don’t want our students to be on public display whilst they are studying. So there is necessarily a privacy.”

6.

The Council’s own 2025 report on the earlier application for this scheme found the 1974 library negative “largely due to its inactive frontage with the street” (report of 29 October 2025 on 25/02161/FUL, paragraph 14.6, page 151). On the applicant’s own section the frontage applied for is, at the height of a person, a wall for its whole length, with its lowest window sill 1.825 m above the lane. The report cannot credit the new frontage as active, or as providing natural surveillance, on the drawing the applicant itself relies on.

The report must give natural surveillance no weight as a public benefit under HE6(4), and must record that the applicant’s own Planning Statement does not claim that the building meets Policy

Page 5

56(d) or (e). If it does, no benefit the applicant’s own documents contradict enters the balance. If it counts natural surveillance as a benefit, or describes the frontage as active at the level of the lane, it adopts a description the applicant’s own section, caption, text and presenter contradict (Mansell at [42]).

3. Light from windows high in a narrow lane goes mostly sideways to the building opposite and little reaches the pavement, and the Council’s own environmental health officer treats the same light as a disturbance to be controlled, so it cannot be counted as a benefit Light on the lane at night is a benefit resulting from the proposal under HE6(4) only if the light reaches the lane. The applicant describes the light as “diffused lighting out of the new library” (section 1, item 1(a)) and has drawn where its windows sit and which way they look (section 2, Exhibit D5). The laws of illumination, applied to that section, send the light mostly sideways rather than down: across the lane to the building opposite, with little reaching the pavement. How much reaches the pavement, and where, is a matter of measurement. No document on the register measures it. The Council’s own environmental health officer treats the light, the internal lighting of the covered Library Court included, as a potential disturbance to the residents opposite, to be assessed and controlled by condition. On the Council’s own advice the light is a disturbance to be limited, not a benefit. If the Council requires the applicant to provide the lighting assessment before any weight is given to the claim, the claim is tested against predicted values and the effect of the same light on the residents opposite is assessed at the same time. If the Council does not require it, the claim rests on no evidence on the file, and the applicant’s own assurance to the residents stands against it (section 1). A report that then gives it weight as a public benefit under HE6(4) weighs a benefit the register does not show and counts as a benefit what the Council’s own officer treats as a disturbance to be controlled. It misleads members on a matter of fact (Mansell at [42]). 1.

Light from a lit window goes mostly sideways rather than down. It is strongest straight out from the glass, it does not run down the face of the wall the window sits in, and it weakens with distance and where it meets a surface at a slant. These are the standard laws of illumination (the lighting profession’s definitions, ANSI/IES LS-1-25, definitions 7.1.1.1, 9.1.1 and 9.1.2).

2.

Applied to windows the applicant itself describes as giving “diffused lighting out of the new library”, the laws send the light mostly sideways rather than down: strongest straight across the lane to the building opposite, 5.665 m away; none down the face of the wall to the pavement beneath the windows; weakened by distance and by angle where it reaches the pavement on the far side. The applicant’s own red dotted lines on page 44 run the same way: from windows A and B across the lane to the apartment level opposite.

3.

The applicant’s own words place the light where the laws place it. The Design and Access Statement states that the windows “are positioned opposite the blank walls or small windows of the commercial floor of the building on the opposite side” (section 1, item 3). The Planning Statement tells the residents opposite, at paragraph 7.74, that the windows are not large enough or so placed that light from inside would disturb them (section 1, item 2). The residents’ windows are across the lane at the same levels as the library windows, 5.665 m away on a level path. The pavement is across the lane and below the windows, so light reaches it on a slanting path that is longer than 5.665 m and meets the pavement at a slant (section 1, item 4). Light too weak to disturb the residents at their windows arrives at the pavement weaker still.

Page 6

4.

The point was put at the DCF, in answer to the applicant’s presenter’s “more light pouring into the lane” (the DCF record, entry 4.20). The petitioners’ presenter, a physicist, replied that “as a physicist I can say that that is not the geometry in which light works” and “We can submit a technical note.” (the DCF record, entry 4.22). This note is that technical note.

5.

No document on the register measures the light. CLAG has found no document that predicts the illuminance the library windows would put on the surface of Christ’s Lane at night; if one exists, CLAG asks the Council to identify it by Tuesday 29 September 2026.

6.

The Council’s own environmental health officer treats the same light as a disturbance to be assessed and controlled by condition. The officer’s response of 20 July 2026 (document 9468203, page 1), reissued on 18 August 2026 (document 9499190, page 1), recommends this condition: “Prior to the installation of any artificial lighting an artificial lighting impact assessment and scheme shall be submitted to and approved in writing by the local planning authority. Internal lighting within the proposed covered Library Court shall also be considered. The scheme shall include details of any artificial lighting of the site and an artificial lighting impact assessment with predicted lighting levels at proposed and existing residential properties shall be undertaken (horizontal / vertical isolux contour light levels and calculated glare levels)”. On the Council’s own officer’s advice, the light from the library is a potential disturbance to the residents opposite, to be predicted and controlled by condition. The applicant’s own answer is the same: “Light will be controlled so that residents are not disturbed at night.” (section 1, item 3). Light controlled so that the residents opposite are not disturbed at night is light kept off the lane at night. A report that counts the light as a public benefit counts as a benefit what its own officer requires to be assessed and controlled as a disturbance, and counts it without any measurement of how much there is.

CLAG asks the Council to require from the applicant, before any weight is given to the claim, a lighting assessment that predicts the illuminance on the surface of Christ’s Lane from the library windows at night, stating the internal lighting levels and the controls assumed. The assessment is to be provided alongside the artificial lighting impact assessment the environmental health officer requires. CLAG asks the Council to state in writing by Tuesday 29 September 2026 that it will require it before the report is written. The date is the one CLAG’s case officer letter of 25 September 2026 sets for the Council’s answers, on the Council’s own time for answering CLAG’s letter of 7 August 2026. If the Council requires it and it is provided, the claim is tested against predicted values and the effect on the residents opposite is assessed at the same time. If the Council does not require it, the claim rests on no evidence on the file, and paragraph 7.74 stands against it. A report that carries the claim as a public benefit weighs a benefit the register does not show, counts as a benefit what the Council’s own officer treats as a disturbance to be controlled, and misleads members on a matter of fact (Mansell at [42]).

4. Every applicant statement on overlooking and light rests on a drawing of the design before the September 2025 amendment, which the Council’s own officer records as superseded, so the assessment must be made again for the building applied for and consulted on again Every statement the applicant makes about overlooking and about light from the windows rests on one drawing: the section across the lane at page 44 of the Design and Access Statement. That drawing is of the design before the amendment of September 2025. It draws the chimneys at level 25.430, 15.095 m above the lane; the controlling drawings on this register, the drawings

Page 7

on which the Council will decide, draw them at 24.530, 900 mm lower. The Council’s own conservation officer records the Design and Access Statement as superseded by that amendment. The applicant has never remade its case on overlooking and light for the building applied for, and the public has never been consulted on such a case. Under section 62(3) of the Town and Country Planning Act 1990 the Council may require the applicant to state its case on overlooking and light for the building on the controlling drawings, and consult on it again. If it does, the report has an assessment of the building applied for. If the report cites page 44 as a drawing of the building applied for, it adopts a drawing the Council’s own officer has recorded as superseded. That is a mistake as to an established fact (E v Secretary of State for the Home Department [2004] EWCA Civ 49 at [66]). If the report relies on the applicant’s statements on overlooking and light without any drawn statement of the building applied for behind them, it carries an assessment of another building as the assessment of this one (Mansell at [42]). 1.

The drawings: (a)

the Design and Access Statement part 2, page 44 (drawing 004700 reproduced), revision P01, 23 May 2025, document 9423961: “Chimney 25430”, 15.095 m above the lane;

(b)

the Christ’s Lane elevation, drawing 004700, revision P03, 22 May 2026, document 9423880: “24530 Top of Chimneys” and “22830 Top of Parapet”;

(c)

Short Section DD, drawing 003703, revision P03, 22 May 2026, document 9423850: the chimneys 14.167 m above the lane and the parapet 12.467 m.

2.

The difference of 900 mm is the reduction made by the applicant’s amendment letter of 27 August 2025 (document 7357152 on the register of application 25/02161/FUL). The Council’s conservation officer recorded on 18 September 2025 (document 7370966 on that register, page 3): “The chimneys have been reduced in height by approximately 900mm”. Historic England recorded on 1 September 2025 (document 9457105, page 1): “The height of the ventilation stacks has been reduced 90cm”. On this application the conservation officer records, on 13 July 2026 (document 9462719) and 26 August 2026 (document 9505685), that the reduction “supersedes the heritage and design and access statements”. The parapet is unchanged at 22.830.

3.

The Planning Statement rests its case that the windows do not overlook the residents opposite on this drawing: “Again, this is demonstrated in the Design and Access Statement” (paragraph 7.74). The drawing is of the building before the amendment, and the Planning Statement, dated May 2025, describes the same building.

4.

The amendment changed the chimneys and the wash up pod, and not the windows. Historic England recorded on 1 September 2025 (document 9457105, page 1): “The overall massing of the building remains unchanged but revisions have been introduced to the chimney/ventilation stacks and the position of the wash up pod, which were raised in our letter of advice dated 29 July 2025.” Exhibit D5 reproduces the section as filed, with the chimney at the level the applicant drew, because it is the only section across the lane on the register and CLAG’s other papers refer to it for the positions of the windows, which the amendment did not move. The applicant’s statements on light and overlooking were made for the design before the amendment and have not been made again for the building applied for.

5.

CLAG’s document accuracy letter of 25 September 2026 asks the Council under section 62(3) to require a Design and Access Statement and a Planning Statement that assess the design applied for under the NPPF, and to consult on them again (that letter, section

Page 8

3). The applicant’s case on overlooking and light is part of what has to be made again for the building applied for and consulted on again. The report must take the building applied for from the controlling drawings. It must record that the applicant’s statements on overlooking and light rest on a drawing of the design before the amendment and have not been remade for the building applied for, and it must require that they be remade and consulted on. If it does, the report has an assessment of the building applied for before it. If it treats page 44 as current, it adopts a drawing the Council’s own officer records as superseded (E v Secretary of State for the Home Department at [66]). If it relies on the applicant’s statements without a drawn statement of the building applied for behind them, it carries an assessment of another building as the assessment of this one (Mansell at [42]).

5. The report counts no benefit from light or surveillance, records that the applicant’s assessment is of a superseded design, and requires the lighting assessment before it is written, or it weighs benefits the register does not show The report must: 1.

give the claim of light on the lane no weight as a public benefit under HE6(4) unless the lighting assessment at section 3 is filed. Record that the claim and the assurance to the residents rest on the same unmeasured light, which the Council’s own environmental health officer treats as a disturbance to be assessed and controlled by condition (sections 1 and 3);

2.

give natural surveillance no weight as a public benefit under HE6(4), and record that the applicant’s own Planning Statement does not claim that the building meets Policy 56(d) or (e). Describe the frontage as the applicant has drawn it: windows from the first floor upwards, none at the level of the lane, and a wall at the height of a person along its whole length (section 2);

3.

take the building applied for from the controlling drawings, and record that the applicant’s statements on overlooking and light rest on a drawing of the design before the amendment. Require them to be made again for the building applied for and consulted on again (section 4).

The frontage is otherwise weighed under Policy 56 and Policy 57 of the Cambridge Local Plan 2018 and DP3 of the NPPF in CLAG’s design and development plan paper and its case officer letter, both of 25 September 2026. The daylight record for the shops and the residents opposite is carried by the design and development plan paper, section 4. If the report does these three things, no benefit the register does not show enters the balance, and the frontage is weighed as drawn. If it does not, it weighs benefits that rest on no evidence and that the applicant’s own documents contradict, and it misleads members on a matter of fact (Mansell at [42]). Requiring the lighting assessment, and the applicant’s case on overlooking and light for the building on the controlling drawings, before the report is written resolves the point.

Appendix A: Exhibit D5 A.1 Exhibit D5 is a version of the applicant’s figure, the section across Christ’s Lane on page 44 of the Design and Access Statement part 2 (document 9423961), captioned by the applicant “Library Windows on Christ’s Lane positioned to avoid overlooking of Bradwells Court on the

Page 9

opposite side of the Lane”, rendered in black, white and grey. Every level, dimension and window label on it is the applicant’s. A.2 CLAG’s additions are in blue: the line at 1.6 m above the lane, labelled as eye height and as a general figure, and the two building names. The applicant’s red dotted lines of view are kept as printed, with the applicant’s figure of a person on the ground floor from which the lines through window C are drawn; its figures at windows A and B, and its room names, are removed. The chimney stands at the level the applicant drew, 25.430 (section 4).

Exhibit D5: the applicant’s section across Christ’s Lane, with the eye height line added Christ’s Lane Action Group (residents@christs-lane.com)

Open the original PDF