Shock vote spells setback for Boris Johnson’s Brexit plans

However although the successful amendment by Tory MP Oliver Letwin passed by 16 votes Mr Johnson continues to insist he will not “negotiate a delay with the EU”.

A critical factor in the vote result is said to have been the decision by Northern Ireland’s ten DUP MPs to vote for the amendment, rather than abstaining.

Opposition leader Jeremy Corbyn said the decision means Parliament “will not be blackmailed” by a Prime Minister “apparently prepared to defy the law”.

SNP parliamentary leader Ian Blackford said the vote was a clear expression that “we cannot crash out on the 31st October” - and said Mr Johnson must be made to “obey the law”.

Liberal Democrat leader Jo Swinson also said the most urgent matter now is that Mr Johnson “complies with the law”.

Speculation continues on whether Mr Johnson has an undisclosed plan to circumvent the so-called Benn Act, which now comes into play, requiring him to request a further extension from the EU.

Mr Johnson has repeatedly insisted he will not ask for one, asserting that he would rather be “dead in a ditch”.

Analysts appear to agree that he must legally send the letter required by the Benn Act by 11pm tonight.

Today’s vote took place amid massive demonstrations in London and across the country.

Many commentators say there is little or no chance of the Brexit legislation being passed by October 31.