The sustainability evidence, 25 September 2026

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CLAG: the sustainability evidence (25 September 2026) The sustainability evidence on the register, set out from Christ’s College’s (“the applicant”) own documents and the Council’s own file, for the findings the case officer’s report to committee on this application (“the report”) has to make on the justification of the building’s volume, mass and bulk and on the weight of its sustainability measures. The applicant’s sustainability reason for how high the building stands above Christ’s Lane is the chimneys. On the applicant’s own words and figures the chimneys give no reason for it: they work by their length, they can start below ground, the Master of the College (“the Master”) accepts this in public, and the energy model credits them with no saving. The applicant gives concrete as its reason for building nothing below ground, then pours concrete below ground and in the chimney wall, and no document compares the carbon of this design with the consented design or any lower design. On the applicant’s own figures the building’s energy efficiency fails the Council’s minimum standard until roof panels are added, and the saving comes from roof panels and heat pumps that need none of the building’s bulk. The Council holds no assessment of the new library against its own standard. This annex makes no request; the requests are in the letters filed with it 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: 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). It states every point it relies on, so that it stands on its own. Quotations are verbatim from the document cited, and documents are cited by their numbers on the register of this application unless another register is named. Where a figure is CLAG’s arithmetic on the applicant’s figures, the sentence says so. Exhibit S17/1, the two passages of CLAG’s transcript of the College’s public meeting of 6 July 2026 relied on at section 1, is filed with it. To: the Council’s sustainability officer (Chris Jablonski, Greater Cambridge Shared Planning), by email; and planning@greatercambridgeplanning.org and PlanningComments@greatercambridgeplanning.org, for the attention of Dominic Bush (case officer), for the public register; 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.

Contents 1.

The chimneys are the applicant’s sustainability reason for how high the building stands above Christ’s Lane, and on the applicant’s own words and figures they give no reason for it

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2.

The applicant gives concrete as its reason for building nothing below ground, then pours concrete below ground and in the chimney wall, and no document compares the carbon of this design with the consented design or any lower design

3.

On the applicant’s own figures the building’s energy efficiency fails the Council’s minimum standard until roof panels are added, and the saving comes from roof panels and heat pumps that need none of the building’s bulk

4.

The Council holds no assessment of the new library against its own standard, and its own file shows that its practice on this site was to assess before supporting

5.

The findings this annex supplies, and where the report’s step on them is stated

1. The chimneys are the applicant’s sustainability reason for how high the building stands above Christ’s Lane, and on the applicant’s own words and figures they give no reason for it HE4(2) of the National Planning Policy Framework of 17 August 2026 (“the NPPF”) requires that any harm to the significance of a designated heritage asset “should have a clear and convincing justification in accordance with the policies in this chapter”. Every heritage assessment on the register but the applicant’s finds the harm in the building’s volume, mass and bulk (CLAG’s harm register, Annex C, filed with this annex, section 1), so a justification of the harm is a justification of the bulk. The one sustainability measure the applicant ties to the bulk is the chimneys. On the applicant’s own words and figures the chimneys work by their length and can start below ground, the applicant’s own energy model credits them with no saving, and the Council has twice permitted a library on this site with no chimneys. 1.

The Master gave the chimneys to the Council’s members as the reason: “We haven’t really dwelt on the green credentials of this building in this DCF but they are very substantial green credentials and that is why the design includes chimneys. And the chimneys need to be a certain height in order to achieve that ventilating effect. That height can begin beneath the ground. But as I’ve said many times, we do not want to dig into the ground. So in order to get this green effect, the chimneys need to be the height they are.” (CLAG’s record of the Development Control Forum of 29 July 2026 (the DCF), filed with this annex (“the DCF record”, cited by entry), entry 4.13; webcast 1:49:16 to 1:49:58).

2.

The only expert evidence on the register is that the chimneys work by their length and can start below ground. A Professor of the University of Cambridge studying sustainability and a Chartered Engineer (“the professor”), in a comment on the register of this application: “it is indeed accurate to state the height of a chimney directly affects its ability to move air passively. Simply put, a taller chimney will move more air. What is not stated is that the height difference has no relationship to ground level. So a chimney that starts below ground level can have the same effect as the same length chimney that starts at ground level. The implication of this is profound for the proposed design. The design could easily be transposed downward and achieve all of its stated passive ventilation objectives. Therefore ALL sustainability claims can be met with a building of lower external height.” The professor made the same objection on the earlier application by letter of 14 September 2025. The Council’s report to its Planning Committee of 29 October 2025 on the earlier application for the identical scheme, 25/02161/FUL (“the 2025 report”) recorded among the objections that the sustainability justification for the

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chimneys was insufficient (paragraph 7.2), and its section on sustainability (paragraphs 15.1 to 15.8) did not answer it. No document on the register of this application answers it. 3.

The Master accepts it, twice in public. At the College’s public meeting of 6 July 2026: “It is absolutely true that if they started deep underground, they could be shorter. But as I’ve explained, we really are not interested in digging a basement.”; and, answering a question: “They could start underground. I’ve explained why it is our decision not to do that …” (Exhibit S17/1, passages 1 and 2, with their timestamps; CLAG invites the College to identify any inaccuracy in them). At the DCF: “That height can begin beneath the ground.” (item 1). On the applicant’s own words the chimneys can start below ground, and the whole building can stand lower.

4.

The applicant’s own energy model credits the chimneys with no saving. The model’s output, appended to the applicant’s Sustainability Statement (Skelly & Couch, revision 2.0, 16 May 2025, document 9423735; “the Statement”) at pages 28 to 31, records no cooling saving, and the chimneys serve the ground floor only: “Façade to ventilation chimney stacks (ground floor)” (the Statement, page 26); “Taller chimneys increase the height of the exhaust air outlet above the ground floor which it serves.” (Planning Statement, Turley, document 9423963; “the Planning Statement”; paragraph 7.28). That floor is “a social hub with tea-making facilities and WCs off” (Planning Statement, paragraph 5.5). To build, the chimneys are part of a wall modelled as “masonry walls & chimneys with connecting concrete slabs to all floors” (the Statement, page 11).

5.

The chimneys were raised and then lowered, and no calculation for either change is on the register. The applicant’s own record of its meeting with officers on 23 April 2025 notes “Grafton Architects’ proposition to increase the chimneys’ height by 1400mm from the previous presentation and VuCity views”, for “functionality/service requirements related to the servicing strategy and further considerations arising from a precedent study of the context of Cambridge” (Design and Access Statement, part 3, document 9423962, printed page 59). In August 2025 the applicant lowered them by about 900 mm: “The taller stacks submitted were based on a number of factors and were the optimal height for solid stacks.” and “… the reduced stacks will still serve their ventilation purpose.” (letter of 27 August 2025, document 7357152 on the register of 25/02161/FUL).

6.

The Council’s own Design Review Panel, with the Council’s Senior Sustainability Officer attending, said on 13 February 2025: “It was suggested to review the operational benefits of chimneys versus their embodied carbon impact for a more balanced approach.” (Planning Statement, Appendix 4). No review is on the register, and no document puts a figure on anything the chimneys deliver.

7.

The Council has twice permitted a library on this site with no chimneys. The consented design, permitted on 5 July 2013 (application 11/0495/FUL) and again on 7 September 2016 (application 16/0405/FUL), places part of its floor area in a basement and stands lower above Christ’s Lane. It was “mechanically ventilated using a displacement system with an air handling unit”, and the Council’s report to its Planning Committee of 31 August 2016 on application 16/0405/FUL, document 2008719 on that application’s register (“the 2016 report”) found that “overall the scheme is energy efficient” (paragraphs 8.38 and 8.39). The applicant’s own reason then was the site: “The Library’s close proximity to the busy shopping centre and the presence of street buskers prevents openable fenestration if quiet study is required.” (Design and Access Statement of 2011, document 577844 on the register of 11/0495/FUL, page 85, read from the page images of the scanned document).

On that record the ventilation is no reason for how high the building stands. The chimneys can start below ground on the applicant’s own acceptance, they serve one floor, the model credits

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them with no saving, and a library on this site has twice been permitted without them. The finding this supplies is that the justification HE4(2) requires is not found in the chimneys (the case officer letter, section 6; the alternatives paper, section 5.2.4, item 5).

2. The applicant gives concrete as its reason for building nothing below ground, then pours concrete below ground and in the chimney wall, and no document compares the carbon of this design with the consented design or any lower design The bulk above the lane follows from the decision to build nothing below ground, on the applicant’s own account: “This accommodation located in the basement in the 2011 proposal has been distributed throughout the new library on the upper floors.” (Design and Access Statement, part 1, document 9423960, section 3.2, page 9). The reason the applicant gives for that decision is carbon, and the reason rests on no figure. 1.

The reason, in the applicant’s words: “The carbon intensity of providing a new basement was also taken into account in the new design, opting for a more sustainable option without a new basement floor.” (Design and Access Statement, part 1, section 3.2, page 9). The Master, in a comment on the register of this application of 8 July 2026, gives the reason as concrete: “They are very carbon intensive, requiring large amounts of concrete to tank them.” At the DCF the Master said a basement “would be about the least green thing we could do” (the DCF record, entry 4.10; webcast 0:29:06 to 0:29:45).

2.

This scheme pours concrete below ground. The Statement models it on a “Piled concrete sub-structure with concrete foundation and ground slab” (page 11); the applicant’s structural engineer states: “The new library will be supported on a piled raft foundation.” (Design and Access Statement, part 3, section 10.3, printed page 65); the demolition and construction plan records “Largest concrete pour twenty-two loads, 1 day” (document 9423970); and the Planning Statement records “some external works including excavation for the raised terrace and service runs” (paragraph 7.117).

3.

This scheme pours concrete in the chimney wall. The Statement models the wall on Christ’s Lane as a “Structural ‘strong wall’ along the Christ’s Lane side comprising masonry walls & chimneys with connecting concrete slabs to all floors” (page 11), with “a reinforced concrete structure along the strong wall” in the intermediate floors (page 26), and the structural engineer states: “The floor and stair construction within the masonry wall/chimney zone is concrete.” (Design and Access Statement, part 3, section 10.3).

4.

This scheme keeps a basement and puts new plant in it: “New plant housed in the basement serving the new building contributes to the overall upfront carbon” (the Statement, page 11).

5.

The Statement’s own breakdown of the scheme’s upfront carbon by building element shows the two largest items as the foundations and piling and the vertical frame. Each stands at about 100,000 on the chart’s scale of kilograms of carbon dioxide equivalent, and no other element reaches half of that. Its breakdown by material lists ready mix concrete for foundations, reinforcement for concrete and ready mix concrete for structures (the charts at page 12). The carbon reason attaches to concrete this scheme pours.

6.

No figure compares the carbon of this design with the consented design or any other lower design. The Statement says a whole life carbon assessment is in progress in One Click LCA (page 11), and none has been filed. The one figure given is for the new library alone (“The upfront carbon is assessed on the new library extent only.”, page 11), so the

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demolition is not counted. No document applies the same model to any other design, and no embodied carbon figure for the consented design was given in 2011 or 2016 either. CLAG’s planning consultant, hgh Consulting, put the point to the Council before the 2025 report was written: “Concrete below ground has simply been replaced with concrete above ground. No comparative evidence has been provided to show that the proposed structure performs better in terms of whole-life energy use.” (objection of 21 October 2025, on the register of 25/02161/FUL). 7.

The 2025 report relied on the reason without a figure: “It is now considered that given the archaeological potential of the site and the sustainability issues arising from extensions to the basement that increasing the size of the building above ground is preferable (as currently proposed).” (paragraph 9.1). The same report recorded the objections “Sustainability impacts from the proposed above ground proposal as opposed to a basement extension.” and “Failure to fully consider the total carbon cost of the proposed development and demolition of the existing building.” (paragraph 7.2), and its section on sustainability (paragraphs 15.1 to 15.8) answered neither.

8.

The applicant’s other reasons against a basement, the site’s archaeology and the fabric of the listed ranges beside Bath Court, are not sustainability reasons. The Council answered both by conditions on the consented design, whose basement stands beside the same ranges (the 2016 report, paragraphs 6.12 and 8.58 and condition 11; the alternatives paper, section 5.2.4, item 7).

On that record carbon has not been shown to be a reason for building nothing below ground: the reason attaches to a basement the scheme keeps and to concrete it pours, and no document quantifies it against the design it is said to rule out. The finding this supplies is that a justification of the bulk found on “no digging” or on carbon adopts premises the applicant’s own documents contradict (the case officer letter, section 6; the alternatives paper, section 5.2.4; the avoidance and justification letter, section 3).

3. On the applicant’s own figures the building’s energy efficiency fails the Council’s minimum standard until roof panels are added, and the saving comes from roof panels and heat pumps that need none of the building’s bulk CC2(2) of the NPPF provides: “Substantial weight should be given to the benefits of improving the energy efficiency of existing buildings and/or drawing energy from district heat networks, renewable and low carbon sources (including through the installation of heat pumps and solar panels where these do not already benefit from permitted development rights) where this would be achieved through proposals for development.” The applicant claims that weight against the heritage harm: “The phrasing ‘substantial weight’ is relevant here when considering the balance against any heritage harms identified.” (letter of 27 August 2026, document 9506331). The weight attaches to the measures the policy names, and on the applicant’s own figures those measures are roof panels and heat pumps that any lower or distributed design carries. 1.

Policy 28 of the Cambridge Local Plan 2018 (carbon reduction, community energy networks, sustainable design and construction, and water use; “Policy 28”) requires new development other than housing to meet minimum standards “unless it can be demonstrated that such provision is not technically or economically viable”, the carbon standard being carbon reduction on the site “In line with the minimum requirements associated with BREEAM ‘excellent’” (Cambridge Local Plan 2018, pages 108 to 110). The applicant reads that standard as “BREEAM 4 Credits (ENE01 minimum for Excellent)” (the Statement, page 4) and as “an EPRNC value of 0.4 minimum” (page 17).

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2.

The applicant’s own result for its efficiency measures: “The results show that with Energy Reduction & Energy Efficiency measures alone (steps 1 and 2 in the CCC hierarchy), the scheme achieves a 11% carbon reduction against the Planning baseline and 3 credits under BREEAM 2018 ENE 01 (using Part L 2021 assessment).” (page 24). Its table gives those steps 0.36 against the 0.4 minimum and rates them “2 (requires improvement)” and “3 (requires improvement)” (pages 21 and 23). So on the applicant’s own figures the building’s fabric, services and heat pumps fall below the Council’s minimum standard.

3.

The standard is reached by generation: “With the proposed use of PVs, the scheme achieves a 38% carbon reduction against the Planning baseline” and 6 credits (page 24), from 32 panels on 60 square metres of roof (page 22). The Statement gives the steps in its own words: “The ASHPs are shown to provide a further 6% saving, and thus 11% saving overall, using the current Part L modelling methodology and carbon emissions factors.” (page 21); “The PVs shown provide a further 27% saving, and thus a 38% saving overall, using the current Part L modelling methodology and carbon emissions factors.” (page 23).

4.

The Council’s own Greater Cambridge Sustainable Design and Construction Supplementary Planning Document, adopted in January 2020 (“the SPD”), separates the two. Its first step “Minimises the energy demand of new buildings through fabric performance and energy efficiency measures”; its last “Supplies energy from new, renewable energy sources” (paragraph 3.2.3). CC2(2) draws the same line, in its words at the head of this section.

5.

Neither the roof panels nor the heat pumps need the building’s volume, mass and bulk. No document says they do, and no lower or distributed design has been assessed for them (the alternatives paper, section 4.5). The consented design carried a ground source system of its own: “It is proposed to have a Ground Source Heat Pump to provide 100% of the heating and cooling demand of the building.” (the applicant’s Sustainable Design and Construction SPD Checklist Documents, February 2016, document 1886123 on the register of 16/0405/FUL, page 13). The Council’s officer supported it and the Council conditioned it (response of 22 April 2016, document 1911693 on that register; the 2016 report, paragraph 8.69). The applicant’s own study for this scheme found an open loop system viable on the College site and no room for it in this design: “… it was determined unfeasible to accommodate the open loop borehole system within Bath Court.” (the Statement, page 23).

6.

The applicant’s own weight for its sustainability measures is “a modest benefit” (Planning Statement, paragraph 8.15), and its own words for the demolition are “in embodied carbon terms, it is regrettable that a building which is only around 50 years old is to be replaced” (paragraph 8.2).

On that record the substantial weight CC2(2) gives attaches to roof panels and heat pumps, which any design on the site carries, and not to the building’s bulk. The building’s own energy efficiency falls below the Council’s minimum standard on the applicant’s figures, and the applicant’s own weight for the measures is modest. The finding this supplies is that the sustainability measures are not a benefit of this building’s bulk and carry no weight for it in the balance (the case officer letter, section 7; the alternatives paper, section 6).

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4. The Council holds no assessment of the new library against its own standard, and its own file shows that its practice on this site was to assess before supporting Policy 28 and the SPD say what has to be assessed and how. On this application the register holds the applicant’s agreement with the Council’s officer on a method, the applicant’s own compliance model, and no assessment. On the same site in 2011 and 2016 the same office checked before it supported, and on the same agenda in October 2025 the Council applied its standard to another new commercial scheme. 1.

Policy 28 allows a bespoke methodology “Where redevelopment/refurbishment of existing buildings is proposed”, as a methodology “to assess the environmental impact of the proposals”, “subject to agreement of the scope of the alternative methodology with the Council”, and supports “Proposals that lead to levels of environmental performance equivalent to or higher than BREEAM” (Cambridge Local Plan 2018, page 111). The SPD requires the demonstration: “Compliance with the policy should be demonstrated by submission of a BREEAM pre-assessment, completed by an accredited BREEAM Assessor, which clearly demonstrates achievement of the BREEAM ‘excellent’ standard.” (paragraph 3.2.8), and that assessment “should be submitted with the planning application” (paragraph 3.8.4).

2.

What is on the register is the agreement and no assessment. The Statement: “This strategy has been reviewed by and agreed with the Sustainability Officer for Cambridge City Council in terms of meeting the Council’s sustainability objectives with regards to Planning.” (page 3). The Council’s sustainability officer’s consultation comments of 18 June 2026 (document 9435149; “the officer’s advice”): “The document outlines a bespoke sustainability strategy for the proposed development based on the RIBA Sustainable Outcomes Guide, as previously discussed at a number of useful pre application meetings. A bespoke approach has been agreed to address the mixed use and variety of new-build and refurbished elements that make up the proposed scheme.” No BREEAM assessment of the new library by an accredited assessor, no record of what the agreed methodology was to assess, and no assessment of its equivalence to BREEAM is on the register. The credit counts are the applicant’s own, from its own compliance model (section 3, item 2).

3.

The officer’s advice is the text placed on the register of the earlier application in July 2025 (document 7323968 on the register of 25/02161/FUL), issued again on 18 June 2026 word for word. The officer’s further comment on the register since August 2026 (document 9500177) reads in full: “I have no further comments to make on this planning application from a sustainable design and construction perspective, my comments of 18/06/2026 still apply.” The advice contains no figure of its own, no calculation and no test of the Statement’s figures.

4.

The same office assessed the consented design before supporting it. On 27 May 2011 the Council’s Senior Sustainability Officer wrote that the application’s omissions were “a little disappointing for a development of this calibre”, that “many areas of this checklist are indicated as being not applicable to this development, and I would query some of these assumptions”, and that clarification was needed “prior to full support being given” (memo of 27 May 2011, document 597600 on the register of 11/0495/FUL). On 6 June 2011, after the applicant’s feasibility report on alternative technologies: “Having checked this information I can confirm that I am in agreement with the findings of this feasibility work”, and “I can now fully support the application.” (memo of 6 June 2011, document 602447 on that register). On 22 April 2016: “the development cannot be supported in full

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until further information related to drainage is provided” (response of 22 April 2016, document 1911693 on the register of 16/0405/FUL). 5.

The Council applied its standard to another new commercial scheme on the same agenda. For item 5 of the Planning Committee of 29 October 2025 the report records “a Sustainability and Energy Statement, BREEAM Pre Assessment, Circular Economy Report, Embodied Carbon Report”, the Sustainability Officer’s comments on “boosting the number of BREEAM credits being achieved to provide an additional buffer”, and conditions for a “BRE Design Stage Certificate, BRE Post Construction Certificate” (the 2025 report, paragraphs 10.224 to 10.227). For this scheme, item 6 of the same agenda, the report repeated the officer’s advice and its four conditions (paragraphs 15.3 to 15.6) and found the proposal “compliant with policies 28, 29 and 63 of the Local Plan” (paragraph 15.8).

6.

The Council’s own validation checklist requires, for all new non residential development, a BREEAM pre assessment demonstrating that the proposals will meet the requirement for BREEAM excellent, and the register holds none (CLAG’s document accuracy letter, filed with this annex, section 4).

On that record a finding that the proposal complies with Policy 28 is made without the assessment the policy and the SPD require, on the applicant’s own compliance model. The Council’s own file shows that on this site its practice was to check before supporting. The finding this supplies is that compliance with Policy 28 cannot be found on the file as it stands (section 38(6) of the Planning and Compulsory Purchase Act 2004; Tesco Stores Ltd v Dundee City Council [2012] UKSC 13 at [18]). The report’s step is stated in the case officer letter, section 7, and the document accuracy letter, section 4.

5. The findings this annex supplies, and where the report’s step on them is stated 5.1 This annex is the sustainability record from the applicant’s own documents and the Council’s own file. It supplies evidence for two findings of CLAG’s case officer letter, filed with this annex (“the case officer letter”). The first is that the building’s volume, mass and bulk has no clear and convincing justification under HE4(2) of the NPPF, its requirement of a clear and convincing justification for harm to a designated asset. The chimneys can start below ground on the applicant’s own acceptance, the carbon reason attaches to concrete this scheme pours, and no comparison with any lower design exists (sections 1 and 2; the case officer letter, section 6; the alternatives paper, section 5). The second is that the sustainability measures the applicant asks the Council to weigh under HE6(4) of the NPPF, its weighing of harm to a designated asset against public benefits, and CC2(2) of the NPPF, its climate change mitigation policy’s substantial weight for energy efficiency and low carbon energy, are roof panels and heat pumps that need none of the bulk. The building’s own energy efficiency falls below the Council’s minimum standard on the applicant’s figures, and the Council holds no assessment against that standard (sections 3 and 4; the case officer letter, section 7; the alternatives paper, section 6; the document accuracy letter, section 4). 5.2 Carrying the record in the words set out in sections 1 to 4, and making the two findings on it, before the report is written, resolves the matters this annex raises.

Christ’s Lane Action Group (residents@christs-lane.com)

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