The Scottish referendum should be the tombstone on 20 years of Labour's "indifference" to the interests of workers, the leader of the country's biggest union said today.

Len McCluskey, general secretary of Unite, gave an impassioned speech to Labour's annual conference in Manchester on the main lesson of the referendum - that "working people matter".

The working class and especially young people had shown their interest in politics and how they had been "electrified" by the engagement.

To loud applause from delegates, he said: "We don't want a constitution made by posh boys in Chequers. We want one made by political debate with the people."

Workers had turned their backs on Labour's advice in Scotland, said Mr McCluskey, continuing: "We can't say we weren't warned. Even after the SNP started winning Scottish parliament seats in the east end of Glasgow, some in the Scottish Labour Party clung to the mantra of wooing the middle classes. It took a referendum campaign to remind us that you ignore the hopes of the working people at your political peril."

The Unite leader said the Scottish vote reflected an upsurge in defence of the NHS, against illegal wars, austerity and inequality.

"It was a triumph of hope against apathy and fear, and our party has to bottle that hope and maybe while we're at it, bottle a bit of whatever Gordon Brown has been taking."

Workers in England and Wales wanted change as much as those in Scotland, because they have had enough of attacks on the NHS, talk of economic credibility with the bond markets rather than the unemployed, and policies trimmed to a few marginal votes in southern England, he said.

"Let the referendum be the tombstone on 20 years of our party's indifference to the interests of the working class," added Mr McCluskey to a standing ovation.