Garden city developments are set to deliver over 400,000 new homes, the equivalent to a city the size of Birmingham, new research has revealed.

A new analysis from the consultants Lichfields has found that Garden Communities are set to provide a total of 403,000 homes, up to 180 new primary schools, 56 secondary schools, and 600 hectares of employment land.

However, the planning and development consultants’ research shows that just 3% of homes have been completed and only a third (34%) are enshrined in adopted local plans or with outline permission.

Lichfields warned it may take five more years before the programme gathers the momentum to make a significant contribution to reaching the Government’s 300,000 new homes a year target.

The consultants found that for around two thirds of the homes in the programme, there remains some planning uncertainty over the principle or scale of contribution arising from their development.

Slightly more than a third (35%) are identified in emerging plans that are subject to independent examination, and 30% are being promoted, but currently have no formal planning status.

Lichfields senior director Matthew Spry said: ‘The scale of the programme is undoubtedly ambitious, and it has progressed further than some ill-fated predecessors – such as “new country towns” and “Eco Towns”.

‘Across the 49 projects, there is a genuine commitment among landowners, developers and local authorities to bring forward fantastic new places for people to live, work and play.

‘While the Garden Communities are unlikely to deliver the lion’s share of their housing allocations until the mid-2020s, they could be delivering 16,000 dwellings a year by the 2030s making a significant contribution to meeting housing need.’

Mr Spry warned that local plans were ‘heavily reliant’ on Garden Communities.

‘On average, one third of local plan targets depend on Garden Communities, but in some cases this is as high as two thirds,’ he said.

‘This means progress in meeting need is subject to the uncertainty associated with local plans, and planning inspectors in some places casting doubt over the principle and/or feasibility of some projects.

‘In these circumstances, any failure or slow-down in delivery will leave those areas vulnerable to planning by appeal.’