Gordon Brown has been urged by a senior government minister not to turn the general election campaign into a "hideous" class war with David Cameron.
Tessa Jowell, the Cabinet Office Minister, warned that it would be a mistake simply to attack the Old Etonian Tory leader for his privileged background.
In an interview with The Sunday Telegraph she said Labour must continue to campaign as the party of "aspiration, linked to opportunity".
Her warning came after Mr Brown used a recent Prime Minister's Questions to accuse Mr Cameron of pursuing policies dreamt up "on the playing fields of Eton".
The move was seen by some observers as a retreat into a "core vote" strategy appealing to Labour's traditional supporters rather than the broad alliance which backed Tony Blair to three election victories.
However Ms Jowell insisted that most voters were simply not interested in such matters.
"I don't think anybody can be responsible for the school they went to," she said.
"Most people don't give it a thought from one day to the next whether Eton exists. I don't think this should be an election campaign about the 1960s intake to Eton, or whatever it was.
"I hope that our campaign - and I believe it will be - will be a decent campaign which is engaging the British people in a conversation, not a hideous to and fro of personality attack," she said.
"This should not be a sort of head-on personality clash between David Cameron and Gordon Brown."