MPs have voted 304 to 0 in favour of a Bill that would enshrine in law David Cameron's pledge to hold a referendum.
The prime minister has pledged to put an in/out referendum to the British people before 2017 should he win the next election.
If it makes it into law, the European Union (Referendum) Bill, introduced by backbencher James Wharton, would make it difficult for any future government, Labour or Tory, to avoid holding a ballot.
Cheerful Tory MPs packed the government benches on Friday morning, frequently intervening as Wharton spoke to congratulate him (and each other) for supporting the Bill.
In a confident performance, 29-year-old Wharton, who ended up in charge of the Bill by chance, mocked Labour MPs and Ed Miliband for choosing to abstain rather than vote for or against the legislation.
"At the next election the public will not forgive Members who do not trust them," he said. "The Labour Party is split down the middle, their leader is too weak to lead. He has ordered them to run away from the debate."
However despite the vote in favour today, the Bill is still highly unlikely to become law as without the backing of the Lib Dems and the Labour Party it does not have majority support in the Commons.
Even so, the prime minister will not bee too concerned as today's piece parliamentary theatre was designed largely as a electioneering tactic. The Conservatives hope to be able to flag up Lib Dem opposition and Labour indecision on the issue of a referendum during the 2015 election campaign.
Tory backbenchers will also publicise their support for the legislation, whether it passes or not, in the battle to defend their seats against a eurosceptic Ukip surge.
Miliband - who was absent from Westminster today - has come under renewed pressure to commit Labour to a public vote when one of his frontbench spokesmen broke ranks to call for a vote to be held even sooner than under Cameron's plans.
Dudley North MP Ian Austin, a former aide to Gordon Brown, wrote in the Express and Star newspaper: "The truth is that the UK needs to decide and I would prefer it to do so more quickly. I know this isn't Labour Party policy, but my view is that we should have a referendum next year on the same day as the European elections."
Labour's shadow foreign secretary, Douglas Alexander, told the Commons said the prime minister had been "driven by weakness" and had cooked up the Bill in Downing Street in order to placate restless Tory MP who did not trust his promise to hold a referendum.
In May, 115 Tories backed an amendment to the Queen's Speech criticising the failure to include a referendum Bill in the government's legislative programme.
"This Bill is not being brought forward because Tory MPs trust the public - it's because they don’t trust their leader," Alexander said.
"This is about external electoral threats and internal leadership threats. Why doesn't the Conservative Party trust the Conservative prime minister? He's sitting there like a hostage on the front bench not like a leader."
He added: "This is a Conservative Party still banging on about Europe, a party talking to itself and not to the country."
However Alexander refused to rule out the possibility that Labour may switch its position - telling MPs the Opposition's policy would be based on whatever was in the "national interest" at the time.
Responding for the government, foreign secretary William Hague drew huge laughs from Tory MPs, as well as a wry smile from Alexander, when he pointed out the apparent divisions within Labour over whether or not to back an in/out referendum.