The former Chancellor of the Exchequer told a packed Commons meeting of the Positive Europe Group - chaired by Michael Heseltine, former Deputy Prime Minister - that he found it hard to explain how a pro-European government had become a Eurosceptic opposition following the party's "collective nervous breakdown" over the past three or four years.
He effectively warned William Hague that if the leadership hardened its opposition to the single currency, as widely expected, party unity could be seriously damaged.
"There is no sensible reason why arguments about the form of words we should use in 1998 to describe our future intentions on Britain's possible entry into EMU [economic and monetary union] should now shatter 50 years of reasonable Conservative unity on the subject of Britain in Europe," Mr Clarke said. If Mr Hague forced the issue, he would be "running the risk of fracturing the party", and the party could "break up" over that form of words.
As for Mr Hague's plans to put such the issue to a vote of party members, Mr Clarke said: "There is no point in having a ballot of all members of the party on EMU when the party can happily hold together those who agree with various propositions. Creating winners and losers will not forge unity.
"A ballot could be highly divisive and any formula agreed might seem quite out of date in a very short time. By the time of the general election, we could have boxed ourselves into an unsustainable position.Reuse content