In a trenchant defence of Labour's promise of referendums on devolution, Lord Irvine of Lairg, the shadow Lord Chancellor and one of Tony Blair's closest advisers, said he was confident of securing a powerful "Yes" vote.
"If the Scottish people say "Yes" in the referendum, will the Conservative Party accept the will of the Scottish people, or will they go on opposing devolution?" he asked, as peers began a two-day debate on the Constitution.
Lord Jenkins of Hillhead, leader of the Liberal Democrat peers, warned of recreating the troubles of Ireland at the beginning of the century if the "settled wish" of the Scottish people was defied.
"It would be an experience which we would be foolish not to have at the back of our minds," the former Labour Cabinet minister told peers.
The Government staged the debate in the hope of wrong-footing Labour over its plans for a "Tartan tax-raising Parliament". Lord Mackay of Clashfern, the Lord Chancellor and himself a Scot, said Mr Blair's proposals contained serious flaws and risked breaking up the United Kingdom.
He told peers the difference in size of the nations of the UK made balanced devolution impossible; Scottish legislation would no longer be scrutinised in a second chamber and investment would suffer.
"It is crucial that the risks of devolution are recognised. I do not believe it is satisfactory to pledge a referendum to be held before a devolution Bill is proposed," Lord Mackay said.
Scots would be voting before knowing how difficulties, particularly financial ones, would be resolved.
But Lord Irvine, in a speech praised by Lord Jenkins as one of the most powerful he had heard in the House, said the Conservative Party had become as autocratic as it was remote: "A large part of the malaise that grips our country stems from a profound disillusion with its system of government."
Labour believes the Government is over-centralised, he said. The institutions of democracy should be brought closer to the people they represented. There was a contradiction at the core of Conservative thinking - "Yes to subsidiarity in Europe; No to subsidiarity in the UK."
Lord Irvine cited enthusiastic support in the early 1970s for a Scottish parliament with tax-raising powers from Margaret Thatcher, the Scottish Secretary Michael Forsyth and his predecessors Ian Lang and Malcolm Rifkind. "How the vision of youth can fall prey to crabby middle age," he quipped.
Reaffirming that Labour would "certainly" campaign for a parliament with tax-varying powers of up to 3p in the pound, he told peers: "The referendum decision is right in principle. It signals no weakening of commitment. On the contrary, the purpose of the referendum is to demonstrate the demand for devolution."