Nick Clegg: Changing UK-EU relations could be catastrophic
Attempts to alter the UK's relationship with the EU could have "catastrophic" results, Deputy Prime Minister Nick Clegg has said.
In a speech, Mr Clegg rebuked those calling for "repatriation" of powers, describing this as a "false promise wrapped in a union jack".
The policy could lead to "an outright crisis" prompting the UK's exit from the EU, he said.
Prime Minister David Cameron has called for a "new settlement with Europe".
A review of the UK's relationship with the EU is being carried out by Foreign Secretary William Hague which is looking topic-by-topic at what is in the UK's interests.
Mr Cameron told MPs last month that as a result of that review he expected proposals to return some powers to Westminster to be "in our manifesto and I think it will get a ringing endorsement from the British people".
Mr Clegg said he thought the idea of repatriating powers was "pretty seductive" and "seemed very reasonable".
"I don't think the EU is perfect by any measure, and I'm a big advocate of EU reform," he said in the speech to international affairs think-tank Chatham House.
But the deputy prime minister claimed that "many of the people who advocate repatriation are the same people who want us out of the EU altogether".
Since "no repatriation of powers would ever be enough" for them, he said, "there is no hard border between repatriation and exit".
He continued: "Heading for the exit would be the surest way to diminish our great country."
It would reduce the UK's clout in Washington, he predicted.
And the UK would have to conform to the majority of EU laws, despite no longer having any input in how they were made.
"To go down that route would be a catastrophic loss of sovereignty for the UK," he concluded.
He also pointed to practical difficulties on how to repatriate powers.
"This idea that we could or should extract ourselves from the bulk of EU obligations is nonsensical. It is wishful thinking to suggest that we could give ourselves a free pass to undercut the single market, only to negotiate our way back into the laws that suit us.
"The rest of Europe simply wouldn't have it.
"If anyone else tried to do that, if the French tried to duck out of the rules on the environment on consumer protection, if the Germans tried to opt out of their obligations on competition and the single market, we would stop them, and rightly so."
In July, a group of Conservative MPs gave details of a "shopping list" of powers they want the UK to reclaim from Brussels as part of a "radically different relationship" with the EU.
The Fresh Start Group, which represents Conservative MPs such as Andrea Leadsom, George Eustice and Chris Heaton-Harris, demanded that powers over justice, energy and agriculture be clawed back.
The MPs also called for a UK veto of EU financial services regulation, far-reaching reform of the Common Agricultural Policy, controls to prevent over-fishing, and UK opt-outs from "intolerable" social and labour market legislation.