Government “blackmail” will force the number of homes in North Somerset to increase by a fifth, planning chiefs say.

Without a new Local Plan setting out where 20,085 will be built by 2038, councillors say decisions will be taken out of their hands and developers will “run rampant”.

The draft document sets out plans for thousands of homes in the green belt, two new villages and vast swathes of employment land, plus supporting infrastructure.

Councillor Mark Canniford told his executive colleagues on February 2: “These choices will challenge us to make really tough decisions in the coming months. We simply can’t say ‘not in my backyard’.

“Any sites removed will have to be replaced elsewhere. If we don’t make the allocated numbers, inspectors will approve developers’ requests anyway – we end up with the buildings and we lose control.

“We’re being blackmailed over these housing numbers, which are much higher than the previous levels.

“We’ll find it very difficult to achieve 20,085 homes. If we don’t, developers will take advantage and put in speculative applications that will ultimately be decided by inspectors. We intend to find the full allocation of housing.

“We’re not happy developing in places like the green belt, but this seems preferable to building people’s homes on flood plains.”

Nearly 3,300 new homes are planned in the green belt.

Cllr Canniford proposed increasing the affordable housing requirement from 30 per cent to an “ambitious” 40 per cent.

But Conservative former council leader Nigel Ashton said developers will argue they cannot provide any other services if the affordable housing requirement increased, and instead suggested reducing the requirement so homes are built that are “truly affordable”.

He said the authority had been arguing for years that the numbers are “ludicrous”.

Cllr Mike Bell said North Somerset needs new homes and local people are best placed to know where they should be built.

“We can make the good decisions that are needed for the people of North Somerset and our future but we can’t do that if we’re constantly having our hands tied behind our backs in terms of the targets set by government, the threat of enforcing national policies and allowing speculative developers to run rampant,” he said.

“My plea to government is to free up local government and local communities to make the right decisions for their areas so that we can get the right decisions for North Somerset and not ones dreamt up in Whitehall by people who know absolutely nothing about our community.”

Cllr Canniford said if residents propose better alternative sites to those in the draft Local Plan when the six-week consultation opens next month, the council will adopt them.

Cllr Ash Cartman blamed a “mutant algorithm” for the housing target.

He said residents question why the council does not simply refuse but explained: “By refusing the prepare a Local Plan we’d end up with this housing growth but your council would lose any ability to influence where housing occurs.”

The biggest development sites set out by the council are at Wolvershill, north of Banwell, where 2,800 homes are proposed, and green belt land south of Long Ashton at Woodspring Golf and Country Club that could see another 2,500 built.

Cllr Cartman said he was pleased the latter would be separate from Long Ashton and not an extension of Bristol but “a vibrant community in its own right”.

Previous plans for a “garden village” at Mendip Spring near Churchill have been scrapped as residents would have been too dependent on their cars to meet climate emergency targets.

The executive unanimously approved holding a consultation on the preferred options. It will run from March 14 to April 29.