Today was the deadline for local councils to get their house in order before the government’s new planning rules come into force.

It’s a key milestone in the battle between ministers and developers who want to increase the housing supply, and pressure groups who are worried that rural England is about to disappear beneath a sheet of concrete.

The government introduced a new streamlined National Planning Policy Framework (NPPF) last year with a presumption in favour of sustainable development.

Councils were supposed to have a Local Plan in place by today, setting out how much housing will be needed in the future and where it should be built.

But the last time we checked only three in 10 English local authorities had finalised the document – a lapse that could leave them badly exposed to land-hungry developers.

Now it’s crunch time.

How many councils have adopted Local Plans?

Just under half the councils in England (47 per cent or 162 out of 343) have formally adopted a Local Plan. You can check whether your area is covered now here.

About seven out of 10 councils have begun the process, but it is a slow one. Of the local authorities who have failed to meet the government’s deadline, about half won’t reach the adoption stage for more than a year, according to new research by the National Trust and the Local Government Information Unit.

Why does it matter?

A council without a Local Plan is at risk of losing control of the planning process.

Say a developer applies for planning permission to build 1,000 new homes in a greenfield site on the outskirts of a town, and the council turns the application down.

The developer can appeal against the decision, and will have a better chance of winning if councillors can’t prove they have set out a proper strategy for housing.

All the planning lawyers and consultants we’ve spoken to say the key question is whether land has been earmarked that will provide a supply of new build sites for the next five years.

Stuart Robinson, head of planning at property services giant CBRE, said: “If local councils haven’t identified that supply they are vulnerable to speculative applications which they may find difficult to refuse. If they are refused, developers will be more willing to appeal.”

Councils across England have already lost legal battles with developers because the courts found they failed to identify enough land for housing.

One planning consultancy told FactCheck they were actively advising clients in the housebuilding industry to target areas where councils have failed to get proper plans drawn up.

This could mean housing developments get the green light against the wishes of local people in areas that don’t have a Local Plan.

(Green)field day for developers?

It won’t necessarily be a free-for-all in areas with no Local Plan. A council may well still be able to block unsuitable developments.

And the NPPF already urges planners to avoid building on green belt land, ensure high quality housing and protect areas of natural beauty. Those principles will apply whether there is Local Plan or not.

In a recent review of the framework, property consultants GVA concluded: “The general pattern of allowing greenfield housing development, (in the absence of) a five-year supply, has not signalled an abandonment of good planning practice, nor is it a charter to allow poor development.

“In general terms protection for Green Belt and other nationally recognised assets has remained strong.”

By Patrick Worrall