David Cameron's brief honeymoon after his stunning election victory has already ended after Eurosceptic Conservative MPs demanded that he win major concessions when he renegotiates the terms of Britain's EU membership.
The Europhobes admit the Prime Minister's unexpected victory has strengthened his position in the party, and insist there will be no repeat of the rebellions over Europe which destabilised John Major's government in the 1990s.
However, they are already raising the bar high on a new EU deal and warning that they will campaign to leave the 28-nation bloc in the 2017 referendum if he secures only cosmetic changes.
One Eurosceptic MP said yesterday: "He has won a breathing space. But we have also won new muscle because he will need our votes in the Commons."
Mr Cameron could usually ignore hardline critics under the coalition as the Liberal Democrats gave him an overall majority of more than 70. But with his majority down to 12, a rebellion by a few Tories could defeat him.
Mr Cameron told Channel 4 News: "The first thing is to get the renegotiation going. We will be doing that soon. I've already made calls to European leaders. Then the referendum. I'm confident we're going to get the right result."
But Peter Bone, a Tory Eurosceptic, said: "We'll see what the British people decide."
Today, the Prime Minister will complete the line-up of his first all-Tory Cabinet. He has already reappointed Chancellor George Osborne, Foreign Secretary Philip Hammond, Home Secretary Theresa May and Defence Secretary Michael Fallon.
Iain Duncan Smith will stay as Work and Pensions Secretary and Baroness Stowell of Beeston will remain Leader of the Lords. Michael Gove returns to the top of government as Justice Secretary and Lord Chancellor. Nicky Morgan is Education Secretary.
Theresa Villiers said yesterday she would find out today if she would remain as Northern Ireland Secretary, but she hoped she would be staying.