The key research questions are:

• How much affordable housing is produced through s106?
• What are the main impacts of s106?
• Is s106 affordable housing additional?
• Who pays?
• Is s106 replacing traditional new build by housing associations?
• Is what is promised through s106 actually delivered?

The evidence

Figure 1: Trends in permissions and completions for s106 affordable housing

The graph shows how completions of affordable housing through s106 have been increasing but not as steeply as planning permissions.

Figure 2: Trends in s106 as proportion of all affordable units

So what is the main impact?

S106 appears to be changing the geography of new affordable housing. It is more expensive because it is being built on more expensive sites and more expensive areas. But most of it is on-site provision so it is meeting the mixed communities agenda.

Main messages from s106 research

The case for linking planning and affordable housing is relatively weak.

But there are practical reasons why it works on its own terms – it is local, it does not go to the general Treasury funds, and it is hypothecated on affordable housing.

There are concerns about how far it can actually increase output and affordability, but it appears to be the ‘only game in town’. Anything that replaces it must be able to do more, otherwise there is no point.

It has proved that something thought to be difficult could work – mixed communities.

But there is a cost – units are getting smaller and social housing overall is being squeezed out.