Highlights downside of not being part of rule-setting process in Brussels

41% of people think that the EU is generally a good thing for the UK

More than half of voters want to leave the European Union, a surprise new opinion poll shows.

Some 51 per cent of people want to sever ties with Brussels, while 49 per cent want to remain in the EU, the Opinium survey for the Observer shows.

It comes as Norway warned Britain not to copy its own situation outside the EU, which leaves it unable to influence key economic rules it must abide by to trade with the 28-nation bloc.

More than half of people would vote to leave the European Union, according to a new opinion poll

David Cameron has promised that if he remains Prime Minister after May's general election he would renegotiate Britain's membership of the EU before staging an in-out referendum by the end of 2017.

Recent opinion polls have suggested support for remaining in the EU, especially after reforms to its workings, was growing.

However, the Opinium survey shows more people would vote to leave in a referendum.

The poll also found that 41 per cent of people think that the EU is generally a good thing for the UK, while 34 per cent said it is generally a bad thing.

Labour has accused the Tories of creating unnecessary uncertainty by raising the prospect of a referendum in two years' time.

Privately some Labour figures think it is the party's only policy which has the backing of business leaders.

However, 29 per cent of people say they most trust the Conservatves to handle the UK's relationship with the rest of the EU, compared to 23 per cent said they most trust Labour. Just 13 per cent said the same of Ukip.

Vidar Helgesen, Norway's minister for Europe, has warned of the downside of not being part of the rule-setting process in Brussels. David Cameron has promised that if he remains Prime Minister after May's general election he would renegotiate Britain's membership of the EU before staging an in-out referendum by the end of 2017

Some Conservatives have argued Britain could leave the EU and have a similar relationship to Norway, which has access to the single market as part of the European Economic Area.

However, Vidar Helgesen, Norway's minister for Europe, has warned of the downside of not being part of the rule-setting process in Brussels.

He told the Observer: 'We [Norway] are fully integrated into the EU single market as members of the EEA, but what we don't have is the right to vote on those regulations that are incorporated into our law when they are made by the council of ministers.'

'You would not have all those Brits staffing the commission where the decisions are made.

'Britain being on the outside would obviously not have that amount of people on the inside. You would find it more difficult, as a result, to affect the regulations.'

Peter Wilding, director of pro-EU group British Influence, said: 'Eurosceptics who peddle the myth that Norway is the best [model] for a non-EU Britain are deceiving the public. They say leaving leads to more democracy and security. This is nonsense.