Kenneth Clarke spoke out for British membership of the European Monetary Union (Emu), saying the single currency could offer the prospect of a stable economy and wealth creation.
Mr Clarke's intervention comes as four ministers, including one member of the Cabinet, prepare to break cover in defence of Europe this week at a conference organised by senior figures on the party's Left.
Environment Secretary John Gummer and three colleagues outside the Cabinet, Ian Taylor, Robin Squire and Nicholas Soames, have all accepted invitations to a one-day conference organised by Mainstream, an umbrella organisation of pro-European groupings.
Yesterday at a meeting with European finance ministers in Dublin to finalise plans for the single currency, Mr Clarke said Lord Tebbit was "out of touch" after the former Tory party chairman told Radio 4's Today programme that John Major should rule out British membership of the single currency.
Mr Clarke said: "I wish Norman would devote his considerable talents to getting the Government elected and not continually trying to open updivision about settled policy. The last thing the Tory party or Britain wants is for Norman Tebbit to keep up unavailing civil warfare in the party."
He accused Euro-sceptics of "knowing nothing" about the way Emu would work. "Good progress" was being made, he said. "I think the single currency could offer prospects of stability, low interest rates, and a zone of economic conditions which attract inward investment and stimulate growth of trade."
One Conservative source said that the Left of the party had decided that "enough is enough".