More than £2 billion will be cut from the schools budget as part of a huge recession-fuelled cost-cutting drive, Children's Secretary Ed Balls revealed.
Mr Balls became the first cabinet minister to set out how the cuts Gordon Brown publicly conceded were needed this week would affect public services.
Up to 3,000 senior school staff, including heads and deputies as well as bureaucrats, could be axed as schools are merged into "federations" run by a single team, he told The Sunday Times.
But most of those posts could be lost by "natural wastage", he suggested.
He warned teachers they would have to accept pay restraint to keep staff on the frontline and said more money could be saved by scrapping the 300-strong "field forces" of Whitehall officials that advise schools on the curriculum.
"It is going to be tougher on spending over the next few years," said Mr Balls of the post-2011 squeeze that will see up to 5% taken off school spending.
Teachers' pay is set by an independent body but Mr Balls made clear his determination that they and other public sector workers should play their part in cutting costs.
"If we are going to keep teachers and teaching assistants on the front line, that means we are going to have to be disciplined on public sector pay, including in education," he said.
Outlining the plans for more joint working between schools, he said: "You might have a head teacher and a team of deputy heads working across the different schools. But we are not going to have larger class sizes."
Reducing senior posts could save £250 million, he suggested, with the "federation" model contributing another £500 million in extra efficiencies. Schools could cut up to 10% of their spending on equipment, facilities, insurance and energy through the sort of joint procurement used in the private sector, officials suggested.
