England's worst performing schools - those categorised under the National Challenge - face redundancies and budget crises from next spring, heads and unions have warned.
Improvements to the "named and shamed" secondaries could stall when they lose vital cash during tough financial times in 2011, the school leaders have said.
National Challenge schools received extra money from the Government as part of the scheme, which aims to tackle poor results and push them above the benchmark of 30 per cent of pupils attaining five good GCSEs, including English and maths.
But heads have said the end of this three-year funding next spring will cause them major problems.
Many used the cash to employ more expensive, experienced teachers and will now struggle to meet their new wage bill. Some have already chosen to become National Challenge Trust schools, because this provides them with a new source of income.
"This time next year this will be a real issue for schools and we are very concerned about budgets in 2011," said Mick Brookes, general secretary of heads' union the NAHT. "The core idea of National Challenge was to provide more funding. If you take that away you are going to have problems."
National Challenge, which started in 2008, was always meant to be a three- year "task and finish" programme to tackle poor GCSE results. Around pound;400 million was allocated for improvements, but the NAHT calculates that only a quarter is given directly to schools. More than half has been allocated to pay for the setting up of academies and trusts.
Unions have constantly attacked the short-term nature of the programme. John Dunford, general secretary of the Association of School and College Leaders, said his members were already planning for when the money runs out.
"This is a common problem with all these time-limited Government initiatives. In order to meet targets schools have to use the money to take on extra staff, then they find themselves landed with the bill when the cash dries up," he said. "With poor funding prospects for 2011 generally . National Challenge schools face particular difficulties."
Helen Salmon, head of St James School in Exeter, is solving her budget problems with pound;450,000 the secondary received after it became part of a National Challenge Trust. "We really need to keep the advanced skills teachers who came in, otherwise there is a danger of a downward spiral," she said.
At Risedale Sports and Community College in Catterick, North Yorkshire, associate principal John Kelly has used his extra pound;79,250 funding to pay for one-to-one tuition. The number of children getting five A* to C grade GCSEs has risen from 18 per cent to 32 per cent.
"Extra resources obviously help schools. It will be challenging to plan for the succession of National Challenge without committed expenditure," he said.
"But to improve exam results there needs to be cultural change as well as extra resources, and it's important we evaluate if this money has been spent well."
The cash was allocated by giving each school involved in the National Challenge programme a "risk rating".
No change, please
Firth Park Community Arts College in Sheffield received pound;120,000 overall, plus a share of pound;750,000 when it became part of a National Challenge Trust.
Headteacher Mo Laycock predicts GCSE results will rise above the National Challenge boundaries this summer.
She has used funding to pay for learning mentors for Year 11 pupils. Class sizes in English and maths have been reduced, there are more higher-level teaching assistants and there is extra one-to-one tuition.
"We don't want changes we have introduced, such as small groups, to end," Ms Laycock said. "Obviously schools would prefer all funding to be permanent. We serve a challenging community, even when results go up that's not going to change. We will have to find a way to keep staffing at this level."
Original paper headline: New blow for `worst' performers as recovery cash runs out