Schools with some of the worst exam results in the country will receive up to pound;140,000 extra over the next two years to help them improve.

But the money, due to be announced in a package next week, comes with strings attached. The 500 schools, which are either failing, have serious weaknesses, or less than 25 per cent of pupils achieving five GCSEs at grades A* to C, will face more frequent inspections.

Between pound;20,000 and pound;70,000 extra a year from next April, will be used to implement raising achievement plans (RAPs) - the latest idea from the Government’s standards and effectiveness unit.

Other measures, expected to be announced at next week’s North of England education conference, include free laptops for heads, internships for aspiring deputies and exchanges with American schools. The package may also include further twinning between weaker schools and specialist, beacon and other schools.

The plans were first suggested at a Department for Education and Employment meeting held just before Christmas for 480 heads. It was addressed by schools minister Estelle Morris. Many of those who attended felt their key concern - staff recruitment - had not been addressed. One delegate walked out in protest and others worried that the threat of extra inspections would put off potential staff.

Nigel Hill, head of Bushey Hall school, near Watford, told The TES that new chief inspector Mike Tomlinson had said the additional visits by ispectors would be supportive.

“The thing that came across loudest (from the conference) was a strong sense of support. This is the first time the Government has made an overt and explicit communication of that support,” he said.

But several heads criticised the Government’s 2006 target of 25 per cent of all pupils achieving five good GCSEs. Secondary moderns in selective areas were particularly unhappy, and others said value-added measures were needed.

John Birchall, head of Millbrook community school in Southampton, said:

“The one thing that’s going to stop me being successful is recruitment. That can’t be solved by schools on their own. The politics of the past few years have achieved some things but had a negative impact on recruitment in difficult schools.”

Other heads said more frequent inspections would make recruiting able staff even harder. “It’s rather a blunt instrument and will hammer some good schools,” said Philip May, head of Oxstalls school, Gloucester. He said: “A regime of inspection is going to deter staff. For the same money, should I go to an “easy” school or one where some of the children are challenging and I’m going to get termly inspection visits? ” John Dunford, general secretary of the Secondary Heads Association, said:

“It is all very well for ministers to talk about raising standards in the lowest-performing schools. But they need to change their measure of performance in these schools, and not just look at the proportion of children getting five A* to Cs.”