Why the Cuba Street Decision Matters for London’s Development Landscape

Background

Newmark’s client, Ballymore, has received planning permission at appeal for a series of scheme revisions enabling the delivery of a 52-storey, residential-led tower, including 434 new homes, a commercial unit and a new public park, located at Cuba Street, Canary Wharf, in the London Borough of Tower Hamlets.

Due to the worsening of the scheme’s viability since the grant of planning in December 2022, a S73 planning application was submitted to increase the number of new homes from 421 to 434 and reduce the number of affordable homes from 100 to 58.

Newmark provided Expert viability evidence at a public inquiry, demonstrating that the revised level of affordable housing was the maximum viable level that the scheme can afford and that the revisions were necessary for the development to be delivered. The legal team included Russell Harris KC of Landmark Chambers and Ashurst, and Planning evidence was provided by Rolfe Judd Planning.

The Case

The Borough and the Greater London Authority (GLA) contested that the reduced amount of affordable housing was the ‘maximum viable’, arguing that the scheme could still viably deliver the consented amount of affordable housing having regard to forecast market growth projections.

Acting for the Appellant, Newmark argued that in order for the development to be deliverable, where such schemes are viability-tested, and there is an expectation that review mechanisms will be used to capture any potential improvements in viability at a later date, schemes should be primarily tested on a present-day basis, i.e. using current day costs and values.

Newmark also argued that enforced front-loading of unknown projected growth risks stalling the development - if imposed, developers will simply wait to implement schemes until such growth has materialised (if at all).

The Outcome

The Inspector allowed the appeal, granting planning permission for the scheme revisions, as proposed. The Inspector largely agreed with Newmark’s case, offering a detailed commentary and rationale for his decision.

The decision is important for the development industry, particularly in London, as it clarifies a number of viability in planning matters, as summarised below.

Firstly, the Inspector agreed that there is nothing in planning policy which precludes the revisiting of viability post-planning permission.

Secondly, he rejected the Borough and GLA’s case that forecast growth in values should be embedded into the viability appraisal used, to set the current viable level of affordable housing at the planning stage.

He agreed with Newmark’s case that because one-way review mechanisms are to be expected under planning policy and guidance, the maximum viable level of affordable housing at the planning stage should be set using present-day costs and values.

The Inspector found that “realism in viability assessment should not be pursued at the cost of deliverability” and that if growth modelling is undertaken to demonstrate that a scheme is deliverable, then it is reasonable to adopt higher target rates of return to account for the increased risk.

The Inspector also found that any ambiguity in the RICS Viability Professional Standard (which the Borough and GLA argued promoted the usage of growth modelling) was a recommendation only and that it does not take priority over the authoritative requirements of the Planning Practice Guidance.

Finally, the Inspector found that the Borough/GLA’s approach could negatively impact housing delivery, running contrary to the Government’s aspirations.

Potential Implications

The Cuba Street case follows the Former Stag Brewery appeal decision, issued in May 2025, and which Newmark also provided Planning advice on. The commentary and reasoning around growth modelling and the usage of review mechanisms is much clearer in the Cuba Street decision, providing clarity on a number of potential ambiguities.

It is now clear that for most developments, viability should be assessed on a present-day basis. In London, where schemes follow the viability tested route, review mechanisms will be used to capture real growth, if this materialises.

The decision has the potential to unlock viability discussions on schemes where higher affordable housing contributions have been sought on a forecast growth basis.

Any future viability guidance to be issued, including the GLA’s Viability London Plan Guidance, will need to accord with the position taken on growth modelling and review mechanisms in the Cuba Street and Stag Brewery decisions.

The decision reinforces Newmark’s position at the forefront of development viability in London – driving clarity and unlocking delivery.

For further information about our involvement in this case, please contact James Brierley, Alex Brown or Alex Vaughan-Jones.