Cornerstone Planning

Highway to Homes

Thomas Horner looks at the role of infrastructure in housing development.

Meeting housing demand in the UK has long come into conflict with lagging transport infrastructure, most notably on our highways.

The Written Ministerial Statement (WMS) set out the Government’s intention to build 1.5 million homes over the new parliamentary term and put a huge emphasis on the importance of housing delivery to the growth of the nation. However, the delivery of homes will not suddenly become easy.

The WMS stressed (albeit briefly and only in the context of releasing green belt land for development) that new schemes must be supported by necessary infrastructure, including transport links. However, in September alone, inadequate infrastructure provision by developers (specifically in respect of roads) led (in part) to several planning appeals being dismissed. 

NPPF Policy

The NPPF currently recommends that “development should only be prevented or refused on highways grounds if there would be an unacceptable impact on highway safety, or the residual cumulative impacts on the road network would be severe.” (NPPF115)

Mind The Gap(s)

The threshold for severity is a matter of planning judgement. A severe determination can block planning approval unless it can be mitigated – albeit that the decision maker ultimately must still stand back and look at the scheme in the round. There is no PPG guidance on how severity should be approached, and so outcomes can vary.

Care is therefore needed in the extent to which:

  • highways effects could reasonably be found to be severe;
  • there are overwhelming reasons for granting permission regardless;
  • mitigation or other schemes can be relied on (including secured by condition); and
  • the information available is good enough or, alternatively, would prevent the decision maker from being able to reach an informed judgment either way.

There will be cases where sufficient uncertainty arising from the technical gaps in assessment work means that a precautionary approach is justified (see Satnam Millenium Ltd v Secretary of State for Housing, Communities and Local Government [2019] EWHC 2631 (Admin)).  That was reflected in the refusal of 500 homes at Mitton, where the Inspector decided that he could not “properly undertake a planning balance of harms against benefits where the likely level of harm is not robustly established” because of uncertainties arising from the technical evidence base.

Recent Planning Appeals

In recent examples, Inspectors have recognised the local need for affordable housing (AH), noting that planning permission should be granted for these schemes unless the adverse impacts of doing so would significantly and demonstrably outweigh the benefits when assessed against the policies in the NPPF as a whole, but gone on to refuse permission.

  • Dudsbury Homes (Southern) Ltd was refused permission for 1,700 dwellings in East Dorset, with highways being one of the principal controversial issues. The Inspector found that, despite the absence of better alternative sites, the adverse impacts on the road network would be severe notwithstanding the proposed mitigation. It was suggested that the scheme would load a large number of additional journeys on to a poor rural road network with seriously negative consequences for highway safety, congestion and inconvenience, and environmental harm. The Inspector felt that it was reasonable to expect sufficient mitigation measures to be laid out at this stage, rather than leaving the issues to be resolved via a s278 Agreement.
  • Gladman Developments Ltd was refused permission for a 500-dwelling scheme, including a primary school that was introduced as part of the appeal. The parties agreed that the NPPF set a high bar for highways capacity refusal but a lack of sufficient traffic modelling and a reliance on an unconnected (and as yet unfunded) highway improvement scheme created a lack of certainty about the impacts on the road network. As such, and following the same rationale that was applied in Satnam, the inspector had to assume that these impacts would be severe.

Take aways

  1. Don’t neglect transport infrastructure – these examples highlight that addressing a housing supply issue in a development application is not enough. If the assessment methods or proposed mitigation measures fall short, so will the entire scheme. 
  2. Take the Hint (in the NPPF Changes): the proposed (July 2024) changes to the NPPF render the approach to measuring the impact of a development on the local highways largely the same. It is suggested that a development should only be refused if the impacts are deemed severe “in all tested scenarios”.  The intention appears to be to nudge applicants to test scenarios properly, but also to control the application of the precautionary approach a bit (but providing a get out where one – presumably credible – scenario shows that severe effects are unlikely).

If this update is adopted, the decision-maker will still need to decide whether that scenario is likely, on balance, or can be made likely (by any scheme controls/ conditions) not to have a severe impact. This will no doubt be an ongoing area of discussion, with many calling for the introduction of clarifying guidance.

Thomas Horner is an Associate in the Planning and Public Law Team at Dentons. This article first appeared in the firm’s Planning Law Blog.