According to the study, there is nothing to prevent developers from sitting on brownfield land until councils are required to free up “more profitable” greenfield.

There is also little to guarantee more houses will be built on the spaces made available, it adds, with many councils still lacking local plans.

The damning report from the Communities and Local Government select committee calls for a full review of the Government’s National Planning Policy Framework. Members say there has not been a sufficient robust evaluation of the policy since its introduction in 2012, and ministers must prove it can “work effectively” to support sustainable development.

The framework was designed to speed up the planning system and deliver more new and affordable homes. This included an emphasis on plans “conserving and enhancing the natural environment.

However, the CLG committee has raised concerns about the lack of measures to prevent developers delaying work on challenging brownfield sites. And the MPs say they are “not persuaded” that the Government’s new Housing and Planning Bill – currently progressing through Parliament – will address this.

“We have particular concerns about the risk that developers will delay developing brownfield sites because local authorities will be required to release more profitable greenfield sites if insufficient housing is delivered to meet local needs,” the group writes.

“The lower viability and higher costs of developing brownfield sites may be a deterrent for some developers.

“The Government should set out how its proposals will overcome the potential cost barriers to the development of brownfield sites, and the steps it will take to encourage the development of such sites in order to meet local housing needs.”

The report also stresses that 34% of local authorities have not adopted a Local Plan setting out their strategic priorities for development, despite the 2017 deadline for submission. According to Government registers, Cornwall, North Devon, Torridge and West Devon councils are all yet to finalise their plans.

Chairman Clive Betts said local authorities should be doing more to identify suitable brownfield sites and protect communities “against the threat of undesirable development”. And he said ministers need to act to put pressure on “dawdling” councils.

Peter Heaton-Jones said many of the issues highlighted in the report are mirrored by in his constituency. He said that the absence of a local plan has created a “vacuum” in the area for “opportunistic” developers.

“I’ve been working with North Devon Council to help finalise our plan as soon as possible,” he said. “As the CLG committee report shows, more than a third of all councils are in the same boat, so we do need to look at this.

“I also share the report’s concern about possible development of greenfield sites. We must always seek to build on brownfield sites first.

“And it would help if developers actually built the homes they’ve been given permission for already, rather than sitting on the land hoping to increase its value.”

North Devon Lib Dem councillor Brian Greenslade said he hopes ministers “will listen and act” on the recommendations of the report. “In my part of the Westcountry we have seen examples of ‘land banking’, and of developers merely obtaining planning permission without any intention of developing sites themselves,” he said.