BRITAIN would lose international influence and be “significantly worse off”, at least in the short to medium term, if it left the European Union, a Hampshire MP said.

Desmond Swayne – who in the past has described Brussels as an “alien and evil empire” and says there remained “plenty wrong” with it today – warned fellow Tories seeking the UK’s exit not to expect life outside the EU to be some kind of “El Dorado”.

The International Development Minister, who was David Cameron’s Commons aide for the first two years of the coalition administration, said he was now more open-minded and would see if the Prime Minister could negotiate a “palatable” new relationship with Brussels.

“My earlier comments don’t have the force they once did, but there’s still plenty wrong with the EU,” he told Total Politics magazine.

“I’m more open-minded. It’s an illusion to believe, as many do, that there's an El Dorado to be had if only we were not in the EU.

“There would be a painful process. It might well in the long-run be more competitive, more prosperous, but we might in the short, medium term be significantly worse off and we’d certainly lose influence.

The key question for me is is that important enough for the political constraints, which are significant in my view, on being a truly independent nation capable of determining our own affairs?

“The Prime Minister believes he can make arrangements on our continued membership of the EU palatable to me. I’ll look at that deal and be guided by his judgment as to whether I ought to live with it or not.”