Mr Hattersley challenged Labour's shadow education secretary, David Blunkett, to give reassurances to the conference in the keynote education debate tomorrow, to end splits which emerged after the publication of the policy document "Diversity and Excellence".
"Thousands of party members - very few of them extremists by any definition - were offended both by the tone and content of Diversity and Excellence," Mr Hattersley told a fringe meeting of the Socialist Educational Association at the Labour conference.
Forty constituency Labour parties have submitted resolutions to the conference, calling for the abolition of grant-maintained schools. The anger in the party at the leadership policy over GM schools is likely to emerge with a composite opposing Labour's policy. The party's national executive has urged its rejection.
Mr Blair has been sharply criticised for softening Labour opposition to GM schools after sending his son, Euan, to the London Oratory, which has GM status.
Labour plans to rename GM schools "foundation schools", and allow them to keep some of their independence, alongside existing comprehensives, known as "community schools".
Mr Hattersley dismissed the idea they could have different but equal status. He said: "If they are the same, why do we bother to make the distinction? I have asked the question time after time this summer and I still have not got an answer.
"All I get is a red herring about church schools. But in the hope of uniting the party, I hope we can rally round the absolute minimum necessary to confirm that the comprehensive idea is alive and well."
Mr Hattersley called on Mr Blunkett to give the following assurances: that most funding will be allocated to the schools with the greatest need; that selection by pre-entry interviews of pupils and parents will be banned to prevent academic selection being replaced by "social selection" ; and all parents in an area should be balloted when grammar schools are incorporated into the system.
"I do not pretend that they would make me an enthusiast for Diversity and Excellence. Nothing which created two distinct sorts of secondary schools can ever be that," he said.Reuse content