Latest figures reveal that 95 former grant-maintained schools, including the London Oratory where the Prime Minister sends his two older sons, get at least pound;100,000 more than equivalent non-GM schools. From April, a special government grant that met part of the cost will be scrapped, so councils could be forced to raid other school budgets.

Detailed breakdowns for the schools, covering 2000-01, show that Dunraven in Lambeth alone received an additional pound;564,680. Bishop Thomas Grant, also in the south London borough, got an extra pound;438,336. Three schools in the London borough of Wandsworth, where six out of the nine secondaries opted out, each received around pound;450,000 more. They are Elliott, Graveney and Burntwood.

The Oratory in Hammersmith and Fulham, where Euan Blair is deputy head boy, received pound;315,634.

The highest amount of additional funding in the primary sector in 2000-01 went to Durand in Lambeth - an extra pound;250,678. Ministers have given an open-ended guarantee that former GM schools will continue to be cushioned despite the end of GM status four years ago. But not all former GM schools benefit.

Last year about pound;32m was given out in transitional funding, with part of the cash coming in special government grants. This year the figure fell to around pound;20m. But the Government has now told councils that from the start of the new financial year in April, it will stop the grant.

Evidence of the extra funding that the former GM schools are receiving has been obtained by The Education Network, a policy and information unit funded by 85 per cent of councils in England and Wales.

Martin Rogers, co-ordinator, said: “It is bad enough that former GM schools continue to receive substantial additional resources that are denied to more needy neighbours. That they should now once again do so at the direct expense of those neighbours is completely outrageous.”

Graham Lane, education chair of the Local Government Association, told councils not to pay the extra when the special grant runs out. Councillors and community schools in Wandsworth have already complained to the Department for Education and Skills.

Malcolm Grimston, council member with responsibility for education in Wandsworth, said: “This is a penalty on schools that didn’t opt out. It is a vicious and unpleasant blow. We were clear supporters of GM but this is setting school against school. The only way we can cover the cash guarantee is by taking the money from the non-GM schools.”

The DFES said ministers did not want transitional funding to continue indefinitely but believed a significant number of ex-GM schools would be in difficulties in 2002-03 if it were axed. A spokeswoman said councils had a duty to provide the funding and that school budgets were likely to rise as a result of higher delegation and the overall effect of the local government settlement.