91Èȱ¬

There is a "strong case" for the British public to decide on the UK's future relationship with Europe in a referendum, William Hague has said.

The foreign secretary said he wanted the UK's EU membership to be a success but "fresh consent" would likely be needed as the institution changed.

David Cameron postponed a major speech on the future of Britain in Europe because of the Algerian hostage crisis.

Mr Hague said the speech would take place at some point this week.

Details of where and when the prime minister would be speaking would be announced on Monday, he added.

In the eagerly anticipated address, Mr Cameron is expected to argue that the UK wants to remain in the EU but on different terms and that a referendum could be held after the next election to give the public their say on the outcome of a future renegotiation.

However, this is likely to depend on the Conservatives winning the next election and other EU nations being willing to agree to changes - including the return of certain powers held in Brussels to Westminster.

Extracts of the speech - released to the media before Friday's planned event in the Netherlands was postponed - suggested Mr Cameron would have warned that the UK could "drift towards" exiting the EU if problems were not addressed.

Mr Hague told the 91Èȱ¬ that policy would be guided by the national interest and while the UK wanted an "outward looking" EU to prosper, the institution had changed a lot since the 1975 referendum which approved the UK's membership.

"We want to get a better relationship with the EU - there are changes we want in that relationship," he told the Andrew Marr show.

"We also need to see how changes in the eurozone are affecting the EU and how that affects this country and the relationship of the countries together.

"But when we have done that there is a strong case for fresh consent in this country and the people of this country having their say."

He said people would need to read the speech as a whole to understand "the context" in which any future referendum might be held.

He added: "It is about... making a success of membership of the EU but also with democratic consent for that in its modern form and the best form that we can bring about."

The Lib Dems and Labour have warned any promise of a referendum in the years to come will cause years of uncertainty, deter foreign investment and increase the possibility of the UK eventually leaving the EU.

Shadow foreign secretary Douglas Alexander said Labour did not not support the status quo in Europe and changes were needed.

While the return of powers should be considered on a "case by case basis", he told the 91Èȱ¬'s Sunday Politics, it was "disingenuous" to pretend - as he suggested many Conservatives were doing - that a wholesale renegotiation was inevitable or even likely.

"David Cameron risks being trapped by his own rhetoric and his backbenchers."

Former defence secretary Conservative Liam Fox, who is one of the Tory MPs who has been briefed on the speech, said he believed the "ideal solution" would be for the UK to remain within the EU but on a fundamentally different basis, focused on trade.

If this could not be achieved, he told the same programme, the British public would have to consider whether they wanted to remain in the EU, adding that while withdrawal would cause "some difficulties" he believed they could be overcome.

And Nigel Farage, the leader of the UK Independence Party, which wants to withdraw from the EU, said he feared that any changes Mr Cameron could obtain from Brussels would be "cosmetic" and the UK risked becoming "a province of a United States of Europe".

"What is really happening is that we will get the speech and then the Conservatives will launch a five-year campaign to try and keep us in the EU," he told the Marr show.

"It is all reminiscent of 1975 when Harold Wilson came back with a cosmetic renegotiation and put it to the country."

Meanwhile the US Ambassador to the UK, Louis Susman, has become the latest senior US figure to warn against the UK leaving the EU.

"We cannot imagine a strong EU without a vibrant partner in the UK," he told Sky News's Murnaghan programme. "That is what we hope will come about but it is up to the British people to decide what they want."