The great density debate – London housing

It is well recognised that London needs more homes, as the “housing crisis” has been the key planning challenge of the last five years if not longer, not just in London but across the UK as a whole. London’s shortage of homes and the inflationary pressures this shortage has placed on housing market has been the key issue that many have tried to tackle and many a policy has sought to address. Yet the discussion and debate continues to roll on, suggesting that there are no immediate answers.

In truth, no single solution is likely to exist - I’m sure even those with the most utopic of outlooks would agree with that. Instead, and as is being more commonly recognised and accepted, a combined range of measures, from the intensification of small infill sites, to new and innovative design, to fundamentally changing the way we think about how we live, are likely to provide the closest thing we may get to an answer that works.

The pressure on London’s housing stock means that the need to increase future housing density is largely inevitable. However, what constitutes ‘optimal’ housing density in different locations, and how London’s policy framework helps to steer this, is a more complicated issue. It is an issue that the Mayor and the GLA are attempting to address through the new look draft London Plan Policy D6 – Optimising Housing Density, which replaces adopted Policy 3.4 – Optimising Housing Potential.

Arguably the most significant and controversial element of the new look policy, taking up the majority of the hearing’s discussion time and dividing opinion across the panel, was the decision by the GLA to remove the Density Matrix, which had been a familiar feature within the London Plan since the first edition in 2004.

Fundamental to the removal of the Density Matrix has been a marked shift in the GLA’s approach away from a numerically driven density policy towards a more qualitative design led approach, with additional design scrutiny required for particularly high density developments. This change in emphasis has certainly not come about overnight, or without due thought and attention.

In 2016, as part of its full review of the London Plan, the GLA commissioned a suite of research studies1 into housing density. Six studies were produced, examining key concepts such as defining and measuring density, and exploring the relationship between density, local character and accessibility. These studies have helped to shape the GLA’s approach to density within the new Policy D6.

Some of the key findings of the research studies include:

• The Density Matrix is not being followed, with 50% of development being above the Matrix maximum for its location, and 25% more than double the maximum;
• The history of the Density Matrix reveals that it was established as an indicative tool of what could be developed on a site, and was not to be used prescriptively. However, its apparent numeric simplicity has led to it dominating the policy approach to density;
• There is no case for continuing to set a maximum acceptable level of density, as there is no universal point at which density is unacceptable; this point is based on personal and cultural perception; and
• There are no inherent problems with recent high density development above the Matrix maximums, and such developments are popular with their residents.

The above findings have gone a long way in shaping Policy D6. As outlined by the GLA in their Housing Topic Paper (2017)2, the new approach to density taken in Policy D6 focuses on the individual site-based factors that are required to deliver successful sustainable residential development, these include – surrounding built form; proximity and access to services; and capacity of supporting existing and planned infrastructure, particularly public transport.

Written representations to Policy D6, and the hearing discussion at the EiP, reveal that the reaction to the removal of Matrix in favour of a more qualitative design led approach has been mixed. One thing that most responders agree upon however, is that the Matrix in its current form, is not working. It is therefore the solution to this problem in policy terms that divides opinion.

Those that advocate the Matrix’s removal point to the fact that it has repeatedly failed against its key performance indicators, and as such is a largely redundant tool which serves only to complicate an already complex issue. They argue that the Matrix should be evaluated on its merits (or lack thereof) in successfully influencing development densities, and that there is no room for sentimentality just because its presence in the London Plan has been so longstanding. The GLA also point out that London was not born yesterday, and that while a numerically driven policy might work for New Towns, where development is started from scratch, London’s venerable urban form is so established and diverse that for a policy to set any kind of numerical target is ultimately futile.

In contrast, those opposed argue that simply removing the Matrix is too drastic a move. Specifically, there is concern that whereas the Matrix acted as a ‘safety net’, which to some degree set the terms of reference for discussions between developers, communities and Local Councils, its removal may result in inappropriate density at both ends of the spectrum. This concern is likely to play out in outer London Boroughs in particular, where the Draft London Plan proposes to focus much of the housing growth expected over the next 10 years, and where there is a danger of both over development and sub-optimal densities coming forward.

These concerns are shared by some community based organisations, who argue that London’s density policy should not be a binary choice between either a numerical Matrix or an open design approach, but rather both are needed, with the Matrix providing an overarching policy framework, within which individual site context and design approaches are framed.

Even those that advocate the retention of the Matrix acknowledge that improvements are needed to ensure its continued value. Again, no consensus prevails on how this can be achieved, but suggestions range from developing a numerically based density policy which can be actually enforced, to attempting to update the existing Matrix to somehow incorporate more of the contextual parameters that influence appropriate density on a given site. This is likely to require a significant amount of work, and given London’s rich urban complexity, it is difficult to see how a new Matrix could possibly reflect the highly unique factors at play in a city such as London. That is not to say that this is a feat not worth pursuing however.

The mixed reaction to Policy D6 can therefore be boiled-down to how density itself is viewed in different quarters. To some, density should be seen as a starting point which helps to shape appropriate development. To others, including the GLA, density is nothing more than a product of site-based context and good design; get that right, and the density is what it is.

The shift in London’s density policy may be welcome news to those who subscribe to the latter approach, but the challenge is now for all of us – Planners, Architects, Developers and Local Authorities, to engage with communities to make this design led approach a reality.

1 https://www.london.gov.uk/what-we-do/planning/london-plan/london-plan-technical-and-research-reports#acc-i-48973
2 https://www.london.gov.uk/sites/default/files/london_plan_topic_paper_on_density_policy_and_details_of_research_-_2017_final.pdf