While many of the specifics have not changed since April, the government has yet to make a decision on some of the key elements of the relief, and its proposed wording may result in some unintended consequences.

The proposed relief

As a reminder, where a scheme provides at least 20% affordable housing, the measure will allow a 50% borough CIL relief to apply to residential floorspace in developments or phases of developments that commence after the relief comes into effect, and before 31 March 2030. The proposed relief is subject to a number of exclusions, qualifying criteria, and procedure.

Excluded land

The government has yet to make a decision on the exact percentage of excluded land that a development site would have to incorporate before it no longer benefits from the incoming relief. Excluded land includes, amongst other types of land, designated Metropolitan Open Land. As part of the consultation the government is asking for the sector’s opinion on the percentage, with options ranging from 10-25%.

Phasing

Compared to previous publications, the latest consultation includes a distinct lack of commentary on phased developments (where each phase is treated as a separate chargeable development so long as the corresponding planning permission explicitly refers to phasing). This is not necessarily a concern, as it is understood that the incoming relief would apply to any qualifying chargeable development of a phased scheme. However, as currently drafted, the proposed amendments to the CIL regulations would seem to create a situation where you would lose the time-limited relief for a previous phase when you come to apply for social housing relief for the next phase of that development.

This would be contrary to the whole purpose of the time-limited relief to help the viability of such developments, and reads as an unintended consequence in the drafting which can hopefully be ironed out through the consultation process.

Viability information

In relation to the viability information required to access the incoming relief, the latest consultation document makes clear that the intention is to avoid onerous and protracted viability discussions. 

It is therefore a welcome change from the initial consultation that the government is minded to pursue the revised approach where applicants would only be required to demonstrate that a scheme is currently financially unviable, rather than proving that the relief alone would move a scheme from an unviable to a viable position.

This remains under active consideration, but we consider very few schemes would be able to benefit from the relief if the revised approach is not adopted given CIL is not the sole consideration in determining whether a scheme is viable or not, particularly in current market conditions.

Rather than preparing a full Financial Viability Assessment (FVA), applicants are required to provide the following:

1. a Summary Residual Appraisal, completed using the prescribed Excel proforma; and 
2. a Statutory Declaration confirming that the inputs and assumptions adopted are fair and reasonable.

The Summary Residual Appraisal incorporates automated analysis and benchmark assumptions against predefined ranges. The intention is that this will reduce the level of scrutiny required by the authority and minimise requests for further information.

While the objective of creating a quick, certain and predictable process is positive, a number of uncertainties remain regarding how the proposed approach would operate in practice:

• Although the latest consultation document states that the information required can be drawn from the applicant’s own appraisals, it also states that the appraisal should be prepared by a suitably qualified practitioner. It therefore remains unclear whether the Summary Residual Appraisal should reflect developer specific assumptions or adopt a market-facing approach, as would typically be required for an FVA submitted in support of a planning application.

• Will the Summary Residual Appraisal be publicly available? A developer’s appraisal is likely to contain commercially sensitive information.

• Who will be expected to sign the Statutory Declaration? The developer or an independent consultant/suitably qualified practitioner?

• Will the proposed process genuinely be less onerous than a typical FVA process undertaken at the planning application stage? For instance, we would highlight that a Benchmark Land Value is required, rather than purchase price, which would typically be prepared by an independent and suitably qualified practitioner. In most cases this requires significant diligence and may lead to prolonged discussions with the authority. Further to this, if the proposed scheme assumptions are required to be market facing (rather than developer specific), then the process is no different to producing an FVA for planning purposes, which requires significant input from independent consultants.

Further clarity is required through the consultation process on the matters identified above. Depending on the outcome, it may be prudent for developers to commission an FVA at the application stage notwithstanding a scheme’s eligibility for the fast track route under the Greater London Authority’s Support for Housebuilding London Plan Guidance. This would provide greater certainty regarding eligibility for incoming CIL relief and could help to expedite the process once the Section 106 agreement has been completed.

CIL charging schedules

The consultation document sets out an expectation that authorities will review and revise their respective CIL charging schedules in advance of the time-limited relief ending in March 2030. The backdrop to this is that many London CIL charging schedules are now over a decade old, meaning that the CIL rates within them have increased by over 50% solely due to indexation, and in a lot of cases are not reflective of the current viability context.

The last CIL charging schedule to be adopted in London (Ealing – December 2025) took around 2.5 years from start to finish, with Croydon’s revised charging schedule on track to take around the same length of time. With the workload of London CIL officers likely to increase because of the incoming time-limited relief, the reality of all authorities updating their charging schedules in time is questionable, especially when there is no statutory timeframe for updating these (unlike with local plans). This raises the question of whether the government should introduce a statutory timeframe for updating CIL charging schedules. And, by extension, whether the government should introduce a mechanism where the incoming time-limited relief from borough CIL is extended until such time as a borough has an up-to-date CIL charging schedule.

Summary

After initially promising to consult on the draft CIL-amending regulations ‘as soon as possible in the spring’, it is positive that the government has finally published its latest proposal for the time-limited relief, along with the extra information, especially around viability. However, there are still a number of unanswered questions and unfixed elements of the relief which will have a material impact on its effectiveness.

The consultation closes on 18 September 2026. Following this, we would expect the final time-limited relief to come into effect before the end of the year. This would create a 3-3.5 year window for potential relief, prior to the commencement deadline closing on 31 March 2030.

Further information

Contact Oliver Milne or Harry Wackett