Densification, Densification, Densification

I’m very relieved that the dust has settled, for now at least, on the first round of consultation on the New London Plan.

One of the most striking aspects of the new Plan is the proposed in increase in London’s housing target from 42,000 per year to 65,000 – an increase of over 50%.  It is largely common ground that an increase is needed, although I’m still not sure that the scale of the increase has registered.

You can see from the chart below that, since the first London Plan, the number of new homes built in London has broadly tracked the target (or vice versa).  And has, generally, gradually increased.  But whilst previous increases have been incremental, what is now proposed is a radical change.  One that we are way off meeting.

(Incidentally, this graph also illustrates the very confusing variety of datasets we have to actually track housing numbers – the GLA’s data is the green line, whereas the others are various Government measures – I don’t know why there are growing disparities between them).

Given that the plan – rightly or wrongly – largely rules out the use of Strategic Industrial Land for housing and entirely precludes green belt release – it follows that we’re going to need a significant increase in density, especially densities on small sites.

But we’ve been talking about increasing densities for ages.  Have we actually managed to do so?

Interestingly (to me, at least) the GLA has finally made the London Development Database available for download, which means that one can actually do some fine-grained analysis on development trends across London, including the change in the average density of development.

Initially, this tells you exactly what you would expect – that Inner London boroughs have considerably greater average development density than outer London boroughs.  Development 101.

But what is more concerning is that – whilst those inner London boroughs have greater development density – there appears to have been very little change in absolute terms in average development density  across London, despite 15 years of a strategic plan urging ever greater increases in density.  In some boroughs, the average density at which new permissions has been granted has actually declined.

The thick red line is the London-wide trend – you can see that it has remained broadly level at around 175 since 2004.

What this seems to suggest is that planning policy has been largely unsuccessful at driving up development density, at least at a London-wide level.

Now, to a certain extent, this isn’t entirely fair – after all, this isn’t showing weighted averages. In other words, a small increase in development density on a strategic site like Greenwich Peninsula or Barking Riverside would lead to very many more homes than a significant increase in density on very small sites, whilst not really affecting the average.

And sure enough, if we look at larger sites, over 1ha, there seems to have been an increase (if only modest) in densities over the last 13 years or so:

BUT – look at the blue line, which is smaller sites (below 0.5ha).  Densities on these sites seem to have remained static or even declined.  Of course, these are the sites that are supposed to delivery a significant proportion of the new homes London needs – from c. 10,000 at present to 23-25,000, according to the new plan.

So the question is, how?  How can the new plan do what the previous two plans have not and, firstly, reverse the downward trend in density on this type of site and, secondly, bring about the sort of step-change it appears that will be need to have any chance of starting to meet housing need?

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