Miliband signals break from Brown-era 'failures'

Less than 72 hours after becoming leader, he will address hundreds of delegates at the party conference in Manchester seeking to win over those who backed his brother David for the job as he declares a "new generation" is now in charge.

Although he will celebrate Labour's achievements during 13 years in office, he will restate his claim to be a candidate for change with a bitter criticism of failures under Tony Blair and Mr Brown, to whom he was a senior economic adviser at the Treasury before entering parliament five years ago.

Although he will vow to keep Labour on the political centre ground, the attack will please those on the left of the party – including the unions which propelled the Doncaster North MP into his job – keen to kill off New Labour but is bound to frustrate loyalists angry at the trashing of the party's record by candidates during the leadership contest.

The claim to have abolished boom and bust of the Tory years was repeatedly made by Mr Brown and Ministers as the economy prospered, but backfired spectacularly when the economy was plunged into crisis.

"Let me say to the country. When you saw the worst financial crisis in a generation, I understand your anger that Labour hadn't stood up to the old ways in the City which said deregulation was the answer," Mr Miliband will say.

"When you wanted to make it possible for your kids to get on in life, I understand why you felt that we were stuck in old thinking about higher and higher levels of personal debt, including tuition fees.

"And when you saw jobs disappear and economic security undermined, I understand your anger at a Labour Government that claimed it could end boom and bust."

Mr Miliband's speech comes amid growing uncertainty over the future of his brother, amid speculation he could walk away from front line politics following his defeat.

And the fact Ed failed to win support from the majority of MPs or party members – relying instead on the unions – has magnified the importance of his speech in reassuring those concerned he may lurch to the left.