Jeremy Corbyn has accused the Government of causing a "crisis in our schools" at a speech to a teaching union.
The Labour leader entered National Union of Teachers's (NUT) conference in Brighton to a standing ovation, and he told delegated the Government's push for academies and free schools would lead to the "asset -stripping of our education system".
His speech comes more than a decade after senior Labour figures stopped appearing regularly at the gathering following the hostile reception given to then-education secretary Baroness Estelle Morris.
The Government's plans to force all schools in England to turn into academies have come under fire from Labour, the unions and Conservatives in local government who will be stripped of the power to run schools in their areas.
He said "there is a crisis in our schools now" with increasing class sizes, teacher shortages and a school places crisis for parents.
"The forced academisation will do nothing to address any of those problems. And yet £700 million will need to be found to fund this needless reorganisation," he added.
He was given a much warmer welcome than Lady Morris, who was heckled and slow hand clapped by delegates in 2002 when she was the last Labour education secretary to speak at an NUT conference.
Afterwards she said: "If I told them that tomorrow was Sunday, I think they'd say it wasn't and pass a motion against it."
Schools minister Nick Gibb said it was "disappointing but not surprising" that Labour is opposing education reforms over the last five years.