New figures suggest that Buckinghamshire is on track to surpass the Government's 2029 target for new houses in the county.

It comes a few weeks after Labour announced changes to the National Planning Policy Framework aimed at achieving sustainable growth in the planning system.

However, an urban policy think tank said England is in a "productivity crisis", and urged the Labour Party to be "much more ambitious" to achieve its 1.5 million housebuilding target over the next five years.

Centre for Cities estimates the Government could still fall 390,000 homes short, even if private development across the country rose to the same level as its strongest-ever period of performance under the current planning system.

Based on historical analysis of housebuilding since the postwar reconstruction period, the think tank's figures suggest proposals may deliver up to 1.1 million new homes by 2029 through the private sector, with the remainder unlikely to be bridged by the public sector.

However, in Buckinghamshire, the analysis estimates that 6,369 houses will be built each year until the final year of the decade, which is over the 5,882 target for the area.

Andrew Carter, chief executive of Centre for Cities, said: “The Government must be much more ambitious for England to reach the bold housing target it has set.

“We’re in a productivity crisis.

“The UK’s big cities are the jobs and productivity engines of the economy, but our planning system doesn’t allow – and has never allowed – them to build an adequate supply of homes for everyone that could work there."

Centre for Cities argues the Government has failed to address the constraints placed on housebuilding by the discretionary planning system in cities and the green belt — which it says is explicitly established to block suburban development.

Mr Carter added: "By removing the discretionary element of the planning system, the UK would bring its planning system in line with most developed economies, remove a big block on housebuilding and enable places to better respond to future rises in demand for homes.

"We have done wholesale planning reform before, and we can do it again.

"What we can’t do is raise national economic growth – and reduce the strain high housing costs place on people’s spending power – if we don’t address the backlog of missing homes."

Over the next four years, private development may fall short by 196,000 new homes in Greater London — 60 per cent under the area’s target — and 96,000 below objective in all other big cities.

A Ministry of Housing, Communities and Local Government spokesperson said: "Despite the dire housebuilding inheritance we are trying to fix, we will deliver the 1.5 million homes our country desperately needs and get Britain building again.

"To get there the Government has already outlined plans to streamline the planning system, restored mandatory housing targets, established a programme to unblock homes stuck in the planning process, and set up a new body to deliver the next generation of new towns.

"On top of this, our Planning and Infrastructure Bill will go even further in overhauling the planning system to boost housebuilding and economic growth across the country."