What was meant to be a crunch vote on Brexit has been delayed after MPs voted by 322 to 306 in favour an amendment withholding approval of Boris Johnson's Brexit deal.
MPs were due to vote on Mr Johnson's new deal today, signalling one of the final steps in securing the UK's departure from Europe.
But an amendment tabled by former Cabinet minister Sir Oliver Letwin, which was intended to force him to comply with the so-called Benn Act requiring him to seek a Brexit extension, has scuppered the PM's plans.
But amid noisy Commons scenes Mr Johnson insisted that he was not "daunted or dismayed" by the result and remained committed to taking Britain out by October 31.
"I will not negotiate a delay with the EU, neither does the law compel me to do so," he said.
And when asked afterwards the Prime Minister's Official Spokesman, when asked if previous statements from ministers that the Government would comply with the law still stood, said: "Governments comply with the law."
Commons Leader Jacob Rees Mogg said the Government is planning to give MPs a chance to have a meaningful vote on the Prime Minister's Brexit deal on Monday.
Labour's Kevin Barron, MP for Rother Valley, and Caroline Flint, MP for Don Valley, defied their party whip to vote against the Letwin amendment.
Both had been tipped to vote for Mr Johnson's deal if it got that far.