Struggling schools in England are to be given more cash to help more pupils get five good GCSEs including maths and English, the Chancellor has said.
Failing schools can be closed as a last resort
£200m is to be spent on the "National Challenge" programme, which aims for all schools to have no less than 30% of pupils reaching that standard.
The target is to have no schools below this level by 2012. Last year 638 did not meet this standard.
Alistair Darling also pledged £60m to help people get workplace skills.
The Chancellor said that by 2011, every school would be "an improving school".
The strategy for the National Challenge will be set out in May, the government says.
It will be based on the London Challenge, where struggling schools were given intensive help to improve.
Officials say local authorities will be expected to have drawn up an action plan for any under-performing schools by the summer.
This will involve a range of options including:
- Sending in experts to help head teachers
- Targeted support to schools for English and maths
- Federation arrangements between schools
- Converting low-performing schools into academies
- Closing schools
On science, Mr Darling said: "I can announce today that we will commit £10m over the next five years - which alongside contributions from the Wellcome Trust and private sector will create a £30m Enthuse Science fund.
"This will give every science teacher in secondary and further education access to high quality professional development helping improve the science offer to today's children."
He said there would be an extra £60m over the next three years to provide new opportunities for people to gain the skills needed to enter work, stay in jobs and progress in their careers.
Shadow Children’s Secretary Michael Gove said £160m of the £200m pledged for pushing up GCSEs had been announced last year.
"Unfortunately it looks like the money for education announced in the budget is not new," he said.
"Instead of more help for children in disadvantaged areas all the Chancellor offered us was yet more spin."
Steve Sinnott, general secretary of the National Union of Teachers, said: "I would have wanted Alistair Darling to commit himself to Gordon Brown's pledge to raise spending on state education to private school levels. The government has not yet set a target date."
John Dunford, general secretary of the Association of School and College leaders, welcomed the extra funding, but said: “Let us be clear that there are not 638 failing schools; there are 638 schools below the government’s ever increasing floor target, now 30% of students with five higher grade GCSEs.
"Of these schools, 250 are performing above average when contextual data is taken into account. That is, the pupils in those schools are already doing better than expected, given their specific needs and backgrounds."
His association's president Brian Lightman, head of St Cyres School near Cardiff, said the budget announcement only served as a reminder of the ever-widening funding gap between schools in England and Wales.
"Consequential funding for Wales from today’s budget provides a golden opportunity for the Welsh Assembly Government to begin to address the inadequacies of Welsh education funding.”