MPs from all parties – but predominantly leafy constituencies - expressed concerns over local plan land supply requirements at yesterday’s Westminster Hall session.
Laurence Robertson, the Tory MP for Tewkesbury, who sponsored the debate, said there was widespread concern that local authorities were being required to re-designate Green Belt land "in order to meet the government’s arbitrary and undefined housing targets".
Lib Dem Cheltenham MP Martin Horward said his authority’s local target was an "econometric model … based not so much on needs as on demand", adding that demand was "insatiable" in some areas.
Boles insisted that targets were not based on surveys asking people where they "fancy living", but "on an understanding of the pressure of demand".
He said household based projections of immigration and the ageing population were the guides of future trends.
"The number of overcrowded families has risen and the amount of space in which young people must grow up has fallen for several decades for a simple reason: Our population has grown and we have not built enough houses to keep pace with it," he said.
"That growth in population has had two main sources. One, which is contentious in the House and elsewhere, is immigration, which was uncontrolled for a long time. We as a party rightly criticised that, and are now doing something to control it.
"However, it is important to remember that the majority—about two thirds—of the growth in population and in the number of households in the country has resulted not from immigration but from ageing. One way that I ask people to think about it is by considering how many people now are part of families in which four generations are alive.
"Quite a lot of them are. It used to be rare to have a great-grandparent or great-grandchild in a family; it is now common, because people are living longer, and they do not all want to live in the same house."
Boles argued that more building on brown-field sites and cracking down on developer "land-banking" could not deal with the nation’s housing shortage alone.
He said: "We are approaching the point at which the number of brownfield sites that are in the right part of the country and are vacant and available for housing development is too small to supply more than a small, although significant proportion — nearly 70 per cent, but not more — of our need."
On the topic of local plans, he said that "more than 50 per cent" of authorities now had the policy documents in place, up from 30 per cent when the National Planning Policy Framework was introduced last year.
However he accepted that the rejection of some councils’ plans due to concerns over the robustness of their land supply figures was a cause of "some frustration".
Asked what he believed was "an appropriate time between an authority agreeing a local plan and it becoming set in stone", Boles replied "six to nine months".
The transcript of the debate can be seen here.