He also told a Commons press conference the Tory party should apologise for the lies told in the 1992 election: "We have to say sorry," he said.
His main onslaught was reserved for Mr Hague. The party's 164 MPs were warned if they voted for Mr Hague to stop himself or Mr Clarke becoming leader, they would repeat the mistake of 1990 and end up with another John Major.
With the three remaining runners vying for the floating votes of about 36 MPs who voted for Peter Lilley and Michael Howard on Tuesday, the pace and the language became sharper yesterday.
Mr Clarke said in a frantic round of media interviews that the party had to come to its senses and elect him as the man able to confront Labour's overwhelming majority.
He suggested Mr Hague had not yet got the style, personality or views to make him a Conservative prime minister. "William one day could play a leading role," he added.
Mr Clarke's side-swipe was as nothing compared to the vituperation of Mr Redwood. "William isn't quite sure whether he wants more European government or less European government. He would like the Europe question to rest there, unanswered, hoping that Europe might go away," he said.
On the single currency, Mr Redwood warned in Churchill- ian tones: "An ostrich Conservative Party will never fly. It will bury its head in the sand at its peril...
"The danger of William's position, as I understand it, is that it leaves the question hanging in the air. The answer has to be never to the single currency."
Mr Redwood accepted Tony Blair's election charge that the Tories had lied in the 1992 election, on tax, VAT on fuel, Europe, the NHS and the recession: "In order to win again, we must first re-establish our reputation for telling the truth."
Iain Duncan Smith, the Redwood campaign manager, said: "One of the reasons why we lost the last election is because the public got to believe that people in this party would do anything, say anything, go behind closed doors and stitch up anything, to stay with their hands on the lever of power."
He said Mr Redwood's campaign was based on the themes of "Honesty, integrity and decency."
Asked how that distinguished him from his opponents, Mr Redwood deliberately impugned their honesty and integrity, saying to the laughter of his supporters: "I have never said they lack decency..."
Mr Redwood said: "I do not want to split the difference, I want to make the difference. I do not want to stop another candidate, I want to win with a positive programme."
Speaking for the campaign team, Mr Duncan Smith said: "You cannot base the electing of a leader on stopping somebody else."
Referring to the 1990 leadership contest, when some MPs voted for Mr Major to stop Michael Heseltine, Mr Duncan Smith added: "We went through this six or seven years ago. If we are to repeat the process, if we look for a stop-gap rather than a stop somebody, we will end up with nothing."
Politics, pages 8 and 9
Profile of Hague, page 22Reuse content