DAVID Cameron has denied he was panicked into bringing forward the Conservatives' draft EU referendum bill to quell Tory unrest as Alex Salmond branded his positioning on Europe "ridiculous".

The Prime Minister, whose visit to the US has been overshadowed by party turmoil back home, insisted he was showing leadership on Europe and acting in the national interest by demanding better terms for Britain.

Despite his assurances, as many as 100 rebel Tories will today vote against the Queen's Speech by supporting an amendment, regretting there was no commitment to a referendum on Britain's membership of the EU in the Coalition's forthcoming legislative programme.

Mr Cameron now hopes his party's draft bill will be allowed debating time in the Commons via the procedure of a Private Member's Bill.

However, the result of the ballot on which an MP gets to put forward such a bill only guarantees debating time to the top five and, when the result of the ballot is announced tomorrow, there is no guarantee a Tory MP will be in the top five.

Even if the bill were to be debated, it would not become law because of opposition from Labour and the Liberal Democrats.

And if, by some chance, it did become law, it would not guarantee a referendum in 2017 as one parliament cannot bind another.

Asked if he had been panicked into rushing forward the draft bill, the PM replied: "Not at all," stressing: "People need to know this is a serious pledge they can bank."

The draft bill shows the question Mr Cameron and his party want to put before the British public in four years' time – do you think the United Kingdom should remain a member of the European Union?

It has echoes of the controversial question, preferred by the SNP Government for the independence referendum – do you agree Scotland should be an independent country? This was regarded as a leading question by critics and, following advice from the Electoral Commission, was changed to – should Scotland be an independent country?

Last night, Mr Salmond insisted the publication of the draft EU referendum bill had fundamentally changed the nature of the Scottish independence debate.

"The UK Government and the rest of the No campaign began the debate on Scotland's referendum by claiming independence would threaten Scotland's place in Europe but the Prime Minister's actions have made that claim look absurd," declared the First Minister.

"The Prime Minister should reflect that those whom the gods seek to destroy, they first render ridiculous."

At Westminster, one Conservative eurosceptic branded Mr Cameron's draft bill announcement, delivered just hours after his White House meeting with US President Barack Obama, "undignified" and a sign of "chaos" in Downing Street. A fellow Tory MP described the draft bill as a "second-best" option and urged the PM to give his backing to a Yes vote today on the rebel amendment.

Labour said the Prime Minister's "weakness" had made Europe a leadership issue for him; his latest initiative was about "trying to get his party back in line rather than getting the economy back on track".

Speaking at a Westminster lunch, Alistair Darling, leader of the No campaign, said the draft bill "smacks of weak government" and compared the current situation to the Tory infighting over Europe under John Major.Meanwhile, Ukip's Nigel Farage said the draft bill was the "last desperate play of a man in a panic" and added: "The EU referendum bill is 490 words long while the Scottish Independence Referendum Bill is over 62,000 words. It's evident this bill was scrawled up on the back of an envelope in a few hours and is meaningless."

As his US tour continued, Mr Cameron teamed up with Prince Harry in New York to promote British industry and tourism, with the two riding into Manhattan together on one of London's new double-decker Routemaster buses. Later, they were presented with miniature dolls of themselves.