Ken Clarke has cautioned David Cameron not to give in to any backbench Tory demand that he draw up a "shopping list" of powers to try and wrest back from Brussels.
The pro-EU cabinet minister said the prime minister should not listen to the "siren voices" in his own party who were determined to see Britain exit the European Union, as he would never be able to make them happy.
Clarke, who is likely to be a leading voice in favour of staying in the union should Cameron's 2017 in/out referendum actually happen, was speaking at an event organised by the Foreign Policy Centre think-tank in Westminster on Tuesday.
The veteran Tory MP said "ingenious" eurosceptics wanted Cameron to agree to push for changes in the structure of the EU that they knew the other 27 members states would never agree to - such as an opt out from the free movement of people - because they did not want him to succeed.
"Such a list would be, I think, quite absurd. We should resist demands to start spelling out demands even if they include slightly more sensible things," he said.
"We should bare in mind that whatever is negotiated by the British and our EU partners over two or three years will be rejected whatever we negotiate by these same hard eurosceptics."
Clarke added: "If the other 27 member states insisted they would present, once a year, a statue in gold of our prime minister as tribute ... that would be rejected by some of my colleagues as a pathetic insult and a mere downpayment on the tribute that was due."
He said even such a generous concession on behalf of the other EU states would only "reenforce their commitment to a referendum".
Cameron has said he will seek to renegotiate Britain's membership of the EU before putting that new relationship to the voters in a referendum. However it is not yet clear what that new relationship would look like, or if one would be accepted by the rest of the union.
Clarke told the meeting on Tuesday in Europe House, the home of the EU in London, that the UK would not be able to succeed in getting any reform if the other member states thought the British government was only motivated by a desire to "cheer-up" its "right wing pressure groups".
Cameron's increased focus on immigration as well as a pledge to hold a referendum has been widely seen as a response to the electoral threat posed by Ukip ahead of the 2015 general election.
Clarke also said those who believed Britain would be able to negotiate global trade deals on its own as easily as it could as part of the EU were "naive".
"The idea that we would be better off on our own, that we don't need to go into the room with the negotiating clout of being the largest open single market in the world and that the clout of 28 EU states, that Britain could get just the same offer out of the hard-nosed men round the Department of Trade and on the Hill in [The US] Congress that we could get as part of the EU is frankly naive optimism and ridiculous," he said.
Clarke added: "We'd take what we were offered, thank you very much. Just as usually in politics we are very close to the Americans and usually we do as they recommend."
Last week Labour and Lib Dem peers killed off Conservative Party plans to introduce a law that would attempt to force the next government to hold an in/out referendum. However Cameron said, despite the defeat in the House of Lords, if he remains prime minister after 2015 one will be held.Suggest a correction