LONDON -- A blunt warning from the United States to Prime Minister David Cameron over his plans to loosen ties with the European Union was echoed by Mr. Cameron's coalition partner Thursday, opening new fissures here over Britain's ambivalent attitude toward the 27-nation bloc.
Nick Clegg, the deputy prime minister and leader of the Liberal Democrats, said risking Britain's membership in the union was perilous, and he mocked a long-awaited speech on E.U. policy that Mr. Cameron is expected to make in the Netherlands before the end of the month.
Mr. Clegg, who is a Dutch speaker and whose party supports the European Union, joked that he would be on hand to translate Mr. Cameron's speech "from double-Dutch to just Dutch."
Mr. Cameron, whose Conservative lawmakers are increasingly critical of the European Union, has said he wants to renegotiate Britain's relationship with the bloc and seek consent from voters for the outcome of those talks.
Many observers expect him to make an explicit promise of a referendum in his upcoming speech -- in part because Mr. Cameron's party risks losing support to the Independence Party, which wants Britain to leave the union.
The political temperature rose following an unusual, on-the-record intervention on Wednesday, in which a senior United States official argued that Britain was a more useful ally if it remained fully engaged in the European Union. Speaking in London, Philip Gordon, the assistant secretary of state for Europe, added that referendums held by other nations on E.U. agreements "have sometimes turned countries inward."
Britons pride themselves on their "special relationship" with Washington, and the possibility that it would be weakened by a movement away from the European Union is problematic for Mr. Cameron.
Addressing parliamentary journalists in London, Mr. Clegg -- who has been increasingly willing to take a different stand from Mr. Cameron on a range of issues -- outlined a vision on Europe starkly at odds with that of the prime minister while asserting that such divisions need not affect the overall coherence of the coalition.
That seems plausible, because practical decisions over E.U. relations will probably be delayed until after the next elections, scheduled for 2015.
"When you have got one in 10 jobs in this country, three million people whose jobs are dependent in one way or another on our position as a full and leading member of the world's largest single market," said Mr. Clegg, "you play with that status at your peril."
"Do we lead or do we hang back in a subsidiary status?" Mr. Clegg asked. "Obviously, the Americans and others, quite understandably, say, 'Right, you are a big nation, you've got big horizons, you've got big ambitions, you've got a big history -- act big, don't act small.' That's my attitude."
One argument in London is that the euro zone -- which Britain never joined -- will seek to integrate further and that this will require a new E.U. treaty. Many of Mr. Cameron's supporters believe that in exchange for agreeing to that, he can wrest back some powers from Brussels, allowing him a new settlement that could be put to voters in a referendum.
But Mr. Clegg said a new treaty might not arise and advised against promising a referendum before it was clear what the future held.
"Why would you provoke a great national debate about nothing very much in particular in response to a document that hasn't materialized yet and might never materialize?" he said.
In a separate development, Gunther Krichbaum, chairman of the European affairs committee in Germany's Parliament, said a referendum "could paralyze efforts for a better Europe and deeper integration."
"Britain would risk being isolated," he was quoted as saying in The Guardian. "That cannot be in Britain's interests."
Mr. Cameron's official spokesman played down the controversy.
"The prime minister's view is that it is in the British national interest to be in the E.U., but he wants to change that relationship with the E.U. and to seek fresh consent for it," he said.world
This article originally appeared in The New York Times.