Building on Oxford's Green Belt may again be investigated after the Government questioned the county's housing plans.

In an assessment of the South East Plan, the Government suggests that the Green Belt may not be left untouched by development and a review of its boundaries should be undertaken.

The Government also raised doubts about the city council's affordable housing policy. It has now asked a panel of inspectors to examine whether the council's target of making 50 per cent of new homes affordable is viable.

Detailed figures for housing development in Oxfordshire and the rest of the region are set out in the draft South East Plan.

This document was agreed after more than two years of negotiations at the regional assembly, under the chairmanship of Oxfordshire County Council leader Keith Mitchell.

But with the plan to undergo examination in public in two weeks' time, the Government has written to the panel of inspectors to spell out its concerns.

The Government Office for the South East (GOSE) urges the inspectors to question whether the proposal to build 28,900 new homes in the region, every year until 2026, can meet demand for housing.

Oxfordshire has agreed to take 47,200 homes, with Bicester, Didcot and Grove absorbing the bulk of them. Now with central Oxfordshire identified as a region for growth, GOSE has raised further questions.

The letter to the inspectors says: "While we would not dispute the high levels of need for affordable housing in Oxfordshire, we are concerned that the policy has neither been framed with a view to the economic viability of sites coming forward, or on the basis of any robust evidence as to whether this policy is deliverable."

Government unhappiness with the plan's implication that no changes would be necessary to Green Belt boundaries is clear.

Villagers across south Oxfordshire have had their fears confirmed this month, with scores of housing schemes being submitted to the district council.

Major new settlements outside Horspath and Thame were put forward, along with sites at Garsington, Chalgrove, Berinsfield, Cholsey, Watlington, Wallingford and Brightwell.

Mr Mitchell said: "No one is going to roll over and surrender. And no-one will be sending bulldozers into the Green Belt just yet."

Oxford City Council leader John Goddard said a review of the Green Belt would be welcome, but re-examination of the city's affordable housing policy was unnecessary.

Eco-fuel may power West

Oxford's regenerated West End could be powered by a new greener energy system.

Oxford City Council is pressing ahead with a feasibility study to see whether electricity and heat could be supplied by a Combined Heat and Power (CHP) scheme.

The city is keen to follow the revolutionary lead of Woking Borough Council in creating its own municipal power company.

CHP stations store heat created in generating power and use it to warm homes, offices or shops nearby. Conventional power plants emit the heat created as a byproduct of electricity generation into the air through cooling towers.

The engineering consultant Arup has now been taken on to investigate the practicalities and cost of introducing a CHP scheme in Oxford.

This week development director Richard Cable said the Westgate would be using a biomass heating system, which involves the burning of waste timber.

But Mr Cable said it would be easy to link this to any West End CHP system.