New data from the Local Councils Network (LCN) reveals a significant 'build-out' gap, with only 52% of homes granted planning permission since 2012-13 actually being completed.

Despite 62 surveyed councils approving over 633,000 units, only 331,300 have been delivered. Currently, more than 200,000 homes hold valid planning consent but have yet to see construction begin.

The LCN identifies four primary barriers to completion:

• Viability: Concerns over profitability and land values.

• Market Demand: Fluctuating buyer interest.

• Developer Behaviour: Strategic delays by landowners.

• Infrastructure Constraints: Lack of essential utilities like water and electricity.

Cllr Richard Wright, chair of the LCN, argued the findings prove the planning system isn't the bottleneck. ‘Councils are approving twice as many homes as are built,’ he stated, calling for a focus on construction delivery rather than just increasing applications.

‘With construction never starting on hundreds of thousands of approved homes, even a modest improvement in build-out rates would make a significant contribution towards meeting national and local housing targets.’

He added: ‘Asking councils to approve even more housing applications, when we already approve about nine in every 10, is missing the point to a complex problem.’

Responding to the LCN's figures, a spokesperson for the Home Builders Federation said: 'Having spent years and significant amounts to get an implementable planning permission, developers would not sit on it and delay their only return on investment without very good reason.

'The majority of these permissions will not yet be at the stage when builders are allowed to start work and will be stuck in the treacle of agreeing final details around planning conditions or highways with understaffed local authority departments.'

Check out: 10 ways councils are responding to new housing and planning policy.