An independent consultant’s report for the Government, which suggests building almost half a million new homes in the West Midlands by 2026, has been dismissed as “fundamentally flawed” by a senior Birmingham City Council planner.

The Nathaniel Lichfield & Partners study said the region’s local authorities could identify sufficient land to build 445,600 dwellings – a quarter more than councils believe is the maximum achievable without intruding into the green belt.

The study was ordered by the Government Office for the West Midlands following unprecedented intervention by Communities Minister Baroness Andrews, who is concerned that the West Midlands is not doing enough to meet national house building targets.

It claims that the additional development can be achieved without spoiling the countryside, a claim rejected by council leaders who fear a requirement to build so many new homes would see widespread growth in sought-after rural areas while brownfield sites in towns and cities are left to stagnate.

Birmingham City Council’s cabinet is backing a draft revision to the Regional Spatial Strategy, which if approved by a public inquiry next year would limit housing growth in the West Midlands to 365,000 new dwellings – including 50,600 in Birmingham.

David Bull, the council’s assistant director of development strategy, described the Nathaniel Lichfield study as a challengeable piece of work based on figures produced by the

National Housing and Planning Advisory Unit which “lacked evidence”.

Mr Bull added: “The Nathaniel Lichfield study is driven by housing supply factors rather than housing needs and it fails to consider the full range of socio-economic and environmental factors that should be taken into account in order to produce a sound plan and the complexity and understanding of sustainable communities.”

He said the report’s findings lacked any understanding of the relationship between greenfield development and urban regeneration. It also suggested a misunderstanding of the house-building industry and over-simplification of the complex relationships between factors such as land prices, planning, housing densities and sales prices, Mr Bull added.

The public inquiry into revision of the Regional Spatial Strategy is likely to see all West Midlands councils join together in opposing the housing figures proposed in the Nathaniel Lichfield study.

If the Government finally accepts the highest ranges of the study, Birmingham would have to find land for 60,600 homes, Solihull 17,600, the Black Country 61,200, Coventry 33,500, Warwickshire 60,500, Worcestershire 50,000 and Staffordshire 57,200.