While the government’s release of land from the Defence Estate for an estimated 17,000 homes and the similar announcement of Network Rail’s hopes to develop another 12,000 homes on its land are to be welcomed, these numbers need to be seen in the context of the government’s five-year target of one million new homes in this parliament.

The government’s target equates to 50,000 new homes per quarter. However, in the last five quarters (including the one starting in April 2015, just before the May 2015 election), only 176,249 homes have been completed, at an average rate of 35,248 per quarter.

To hit the government’s one-million-home target by 2020, completions will now have to average 54,917 for each of the next 15 quarters, over 50% more than the present rate of completions. This gap will only get wider with each quarter that passes without the required rate being met.

Each of these sites will need to be marketed, planning permission will need to be obtained, reserved matters will need to be approved and then the myriad other planning conditions that are associated with large developments will need to be discharged. Larger sites are likely only to be built out at a rate that the local housing market can absorb, leaving many likely delivery dates after 2020.

The announcement from the Defence Estate is not going to change the simple inescapable arithmetic: the government is unlikely to see the amount of housing it is targeting get built, which of course is no reason for it not to keep trying…

Carl Dyer, national head of planning at Irwin Mitchell