The number of homes being planned on green belt land in England has increased to more than 360,000, according to countryside campaigners, who fear ministers are poised to weaken protections to meet ambitious building targets.

The assessment by the Campaign to Protect Rural England (CPRE) found that the number of homes planned on sites previously meant to block urban sprawl has risen from 81,000 in 2012 to 362,346, with the largest number slated for development in the north-west and east of England.



Open fields owned by Oxford colleges including Magdalene and Brasenose and sites close to the New Forest in Hampshire are among the green belt areas that could contain housing.

The threat comes as Sajid Javid, the communities secretary, prepares to launch a new national housing policy, expected in the coming weeks. He recently praised Birmingham city council for allowing housebuilding on green belt, but he has also described green belt as “absolutely sacrosanct”.

The most dramatic example of a threat to green belt land is around Manchester, where thousands of hectares have been identified by planners for about 50,000 homes. Andy Burnham, the former shadow home secretary who is running to become mayor of Manchester, this week warned that this development would “diminish quality of life in some communities and restrict people’s access to good air and green space”.

The Jockey Club, which owns Kempton Park racecourse in Surrey, this week asked the local council to zone it for 3,000 houses in a move that sparked anger from local residents and allegations of an “unwanted desecration of desperately needed green belt” from the council leader, Ian Harvey.

The number of homes granted planning permission annually in green belt rose fivefold from 2,258 in 2009-10 to 11,977 in 2014-15, according to the House of Commons library. The net loss of green belt between 2004 and 2014-15 amounts to 41,570 hectares (103,000 acres).

Environmentalists claim the spread desecrates Britain’s natural environment, but housebuilders and some planners argue the increase still means that only a small fraction of the country is urbanised. The release of green belt is essential to boosting the number of new homes, which remain short of the 250,000 estimate of annual need.

Protection of green belt is highly sensitive for the government. Theresa May and Javid are among many Conservative MPs whose constituencies contain green belt and are under pressure to build more housing. The party made protection of the green belt a manifesto commitment, but has also pledged to tackle the housing crisis.

Facebook Twitter Pinterest Green belt land near Wigan where there are proposals to build hundreds of houses and a motorway link road. Photograph: Christopher Thomond/The Guardian

The housing minister, Gavin Barwell, has said “most new building [on green belt] is inappropriate”.

“The government speaks with forked tongue on the green belt,” said Michael Tyce, a local CPRE activist campaigning against proposals for 17,000 homes on protected land around Oxford. “It says it will die in a ditch to prevent it, but it keeps allowing building on it.”

Ministers are able to open up the green belt for construction without expressly ordering it. Whitehall obliges councils to produce local plans to meet housing demand. If these include rezoned green belt, the secretary of state can decide whether or not to call it in. If he does not, then he is in effect granting tacit approval, but is able to say the decision was a local one.

A spokesperson for the Department for Communities and Local Government said of the CPRE figures: “These claims are based purely on projections in local plans, including those not yet adopted. This government is committed to protect the green belt. Only in exceptional circumstances may councils alter green belt boundaries, after consulting local people and submitting the revised local plan for examination.

“We’ve been absolutely clear that councils must prioritise development on brownfield land, and have announced plans to radically boost brownfield development and bring life back to abandoned sites.”

Housebuilders described green belt boundaries as “historic and arbitrary lines on a map”.

Andrew Whitaker, the planning director at the Home Builders Federation, said: “A strategic review of green belt policy could better ensure that this broad-brush policy evolves to cover the type of land many believe it was set up to protect, such as areas of natural beauty and gaps between settlements, while allowing the country to address our housing crisis in a sustainable way.”

Shaun Spiers, the chief executive of the CPRE, said: “The government faces a choice. It can either continue to set inflated and undeliverable targets that fail to increase building rates and force the release of green belt land and other countryside for development. Or it can set realistic targets and get the nation behind building the new homes we need.”

Hugh Ellis, the head of policy at the Town and Country Planning Association, said the government needed to move to a more strategic approach to housing by planning several substantial new settlements, if green belt is to be protected. He said that after the second world war the policies of designating green belt and building new towns operated together.

“What has happened is we have stopped building the new towns, but have kept the green belt,” he said. “It is not surprising we have a housing crisis.”

Local politicians are growing increasingly resigned to the need to allocate protected land for housing, with 58% of councillors who preside over green belt saying that their council will do so in the next five years, according to a survey by the Local Government Information Unit and the National Trust.

“There are concerns the new housing white paper, expected later this month, could make matters worse, if it sets rigid housing numbers for local plans that don’t take account of local factors such as green belt and areas of outstanding natural beauty,” said a spokesperson for the National Trust.