If a week in politics is a long time then a year must be an eternity, but it is now almost 12 months since West Midlands council leaders reluctantly offered Whitehall a compromise by agreeing to plan for 362,000 new homes to be built across the region by 2026.

But the local authorities’ strategy has been blown apart by the Government which is now actively seeking ways in which to force that figure up to 446,000.

The pressure for development that such a big total implies is becoming clear in Birmingham, where council leaders find themselves in a somewhat compromised position since they have already approved a strategy to increase the city population by 100,000 which, we have been assured in the past, will not mean building houses on the green belt.

A draft Local Development Framework, to be presented to the cabinet next week, finally puts paid to the ludicrous pretence that rapid expansion of Birmingham can be achieved within the 20-year timetable by sticking to developing brownfield urban sites. In a document which planning officials suggest, perhaps with unintentional understatement may generate much debate, details are given of seven green belt sites to the north-east and south of Birmingham where new eco-settlements” might be developed.

To quote from the document directly: “The Regional Spatial Strategy Phase 2 Revision currently requires Birmingham to provide an additional 50,600 dwellings between 2006 and 2026. This figure is a minimum. A higher inspirational target of around 65,000 dwellings would increase the likelihood of achieving the population growth in the context of the Growth Agenda.”

It is of course perfectly possible that the cabinet will reject the green belt development option, in which case Birmingham’s 100,000 population-growth agenda is placed at risk. On the other hand, council leaders may decide that Government pressure to identify additional land for new housing leaves them with no option but to encroach into the countryside, even expanding into parts of Staffordshire and Worcestershire.

Spare a thought for Peter Douglas Osborn, the new chairman of Birmingham planning committee, who made his name as an unswerving champion of the green belt and less than a year ago told his colleagues: “There is a line that must not be crossed. We should say the brick stops here.”

Yesterday, Coun Douglas Osborn was left to reflect that the green belt may not be sacrosanct after all.