Rounding on Labour's proposals to reform the House of Lords, starting with an end to the hereditary system, John Major said he did not believe the changes were "relevant to the problems and opportunities" facing the country.
"It seems to me that that particular reform is an irrelevance and it is intended to be a spiteful, thoughtless irrelevance as well," he told MPs at Question Time.
Tony Blair's plans for the Lords, reaffirmed on Wednesday, would begin with the abolition of the right of the 769 hereditary peers, some of whose titles date back to the 13th century, to speak and vote. The more hardworking of them could be made life peers, but ultimately Mr Blair wants an elected second chamber.
Raising the issue, Dame Jill Knight, Tory MP for Edgbaston, said the Lords provided "a very useful and important advisory service for this country at very little cost". Apparently ignoring Monday's crushing defeat over TV sport, she asserted the Lords had no power to frustrate the Commons.
Later, during questions on future business, Bruce Grocott, Labour MP for The Wrekin, said the hereditary right to legislate was "bizarre". He had nothing against the descendants of Charles II's mistresses but was "baffled" as to why they should have the same right to make laws as people who had been elected.
Pointing to the TV sport vote, Tony Newton, Leader of the House, said he was "mildly surprised" at Labour's hostility. Of the hereditary peers who took part, 88 voted against the Government, including 36 Conservatives, seven Labour, nine Liberal Democrats and 36 crossbenchers. Sixty Tories and one crossbencher voted with the Government.
The sharpest exchanges were over the looming Scott report on arms for Iraq, with Mr Blair referring to "a concerted attempt to rubbish the inquiry" and Mr Major sidestepping demands to say whether it had been conducted fairly.
"I asked Sir Richard [Scott] to carry out that report and I have every confidence that he will do and has done so thoroughly," the Prime Minister repeated. The tenses seemed confused as Mr Major and ministers involved in preparing next Thursday's statement have already received copies of the report.
To groans of mock sympathy from Tory backbenchers, Mr Blair complained that Labour would only get the 2,000-page report a few hours before publication while ministers and four Government departments would have had it for eight days.
He said he was not asking the Prime Minister to comment on the findings but on whether the inquiry was fairly conducted or not. "If he isn't going to say that, then the final vestiges of respect will be removed from his government." But Mr Major simply repeated his earlier formula.
Geoffrey Hoon, Labour MP for Ashfield, said Lord Howe, the former Foreign Secretary, and others had "sought to impugn the integrity of Sir Richard" and attack the contents of the report before publication.
There were also grumblings on the Tory side over the Government's refusal to allow backbenches time to digest the report before the statement. Mr Newton said there was no precedent for doing so, and MPs would be able to study it before a full debate on Monday 26 February.
Appealing for a rethink, Richard Shepherd, Conservative MP for Aldridge Brownhills, said MPs elected on an equal franchise should have access to the report on the same basis as the Labour frontbench.