The Government has won a vote against holding a referendum on Britain's future in the EU - but as many as 82 Tory MPs defied the Prime Minister.
David Cameron had issued a last-minute appeal to his MPs as he faced the biggest rebellion of his leadership.
Tory backbenchers had been ordered to vote against the motion calling for a referendum on whether the UK should remain in the EU , leave it or renegotiate its membership.
However, dozens of backbenchers and junior members of the Government defied orders.
In the end, the Government comfortably won the vote with a majority of 372.
But the 111 ayes for the motion included up to 80 Conservative MPs - a significant assault on Mr Cameron's authority.
Before the House began debating the motion, the PM insisted now was not the right time for a referendum.
"Those who are supporting today's motion, but don't actually want to leave the EU I say to you, I respect your views, we disagree about ends, not about means," he said.
"I support your aims. Like you, I want to see fundamental reform. Like you, I want to refashion our membership of the EU so it better serves our nation's interest.
"The time for reform is coming, that is the prize. Let us not be distracted from seizing it."
Conservative MP Adam Holloway told the House he was resigning his unpaid Government job as a parliamentary private secretary (PPS) in order to be able to vote for a referendum.
"If you can't support a particular policy, then the honest course of action is to stand down," he said.
"I want decisions to be made more closely by the people they affect, by local communities, not upwards towards Brussels.
"I'm not now prepared to go back on my words to my constituents."
Parliamentary aide Stewart Jackson also effectively fell on his sword, telling MPs: "For me constituency and country must come before the baubles of ministerial office."
More to follow...