LONDON (AFP) -- David Cameron barely had time to toast his stunning election victory before attention turned to Britain's future in Europe and the onerous task of quelling rebellious eurosceptics within party ranks.

During his victory speech, Prime Minister Cameron said he would stick to his pledge to hold an in-out referendum on Britain's European Union membership by the end of 2017.

Cameron will campaign to stay in the union, but only if he can secure reforms such as changes on migration and benefits, and the repatriation of certain powers to London.

However, he will have to simultaneously appease his European partners and the anti-EU faction of his own party, whose influence is amplified by the Tories' narrow majority of just 12 seats.

"Every step of the way he will have to manage a caucus of up to 100 eurosceptic rebels who are not likely to be satisfied with merely tearing up red tape," warned the Times editorial on Friday.

Cameron held sway over his MPs during the last parliament as his coalition with the centrist Liberal Democrats gave him a sizeable majority, diluting the influence of backbenchers.

The new situation has raised comparisons with that of former prime minister John Major, who was tormented by Tory rebels during Maastricht Treaty negotiations, famously calling three of his own cabinet members "bastards".

"Cameron's greatest challenge lies elsewhere, in the looming 'return of the bastards'," commentator Simon Jenkins wrote in the Guardian.

He said the referendum strategy "ideally involves Cameron pleading with Germany's Angela Merkel for sympathy and gifts.

"Ideally, he will have a referendum and ideally he will win. But if ideally does not somehow come to pass, the revenge of the bastards will be savage," Jenkins added.

One of the cabinet members believed to have been targeted by Major's tirade is still a serving MP.

Cameron may try to capitalise on his current popularity and force through change before the summer.

He is set to send finance minister George Osborne and foreign minister Philip Hammond, to Berlin and Brussels to negotiate a new deal, according the the Sunday Times.

But it also reported that up to 60 rebel MPs were preparing to demand new powers for the Commons to veto any EU law, a plan Cameron previously called "impossible".

Financial Times writer Philip Stephens said that Cameron was the "author of his own predicament".

"By demanding a new settlement and setting a 2017 deadline for an in-out referendum, the prime minister has offered himself as a hostage both to his European partners and to the hardline eurosceptics in his own party," Stephens said.

Like Major, Cameron has filled key cabinet roles with eurosceptics in a bid to placate potential rebels, while alarming Brussels.

Straight after victory on Friday, Cameron announced that Hammond and Michael Fallon would keep their jobs as foreign minister and defence minister. Both men have said they would vote to leave the EU if powers were not brought back from Brussels.

But experts warned that Cameron could find it tough to secure major concessions, given the legal barriers.

Cameron is especially keen to clamp down on "welfare tourism" by imposing restrictions on EU migrants' access to benefits.

"Cameron can get something on immigration, access to in-work benefits, restrictions on access to health service, all of these things are feasible without treaty change," Professor Sara Hobolt, a European politics and European electoral behaviour expert at the London School of Economics, told AFP.

"But he can't get something on freedom of movement of labour."

His reputation in Brussels could also count against him during negotiations, she argued.

"In the past, Cameron has antagonised some of his European colleagues," Hobolt said.

"He's certainly raised some eyebrows. It's not really the EU way of working, which is very much about building bridges and alliances."