Boris Johnson's government has lost its majority after one of his Conservative MPs defected ahead of a crucial Brexit vote this evening.
Dr Philip Lee crossed the floor of the House of Commons while the Prime Minister was speaking, to join the Liberal Democrats, blaming his former party's Brexit policy.
Johnson has repeatedly said Britain will leave the EU on the 31st of October, come-what-may.
Tonight Conservative rebels are attempting to pass legislation that would help block a no-deal Brexit.
(SOUNDBITE) (English), BRITISH PRIME MINISTER, BORIS JOHNSON SAYING: "This is not a bill in any normal sense of the word.
It is without precedent in our history.
It is a bill that if passed would force me to go to Brussels and beg an extension.
It would force me to accept the terms offered.
It would destroy any chance of negotiation for a new deal.
It would destroy it." But when asked directly - he said he would obey the new law, which would give MPs control of parliamentary proceedings.
(SOUNDBITE) (English), BRITISH PRIME MINISTER, BORIS JOHNSON SAYING: "I'm grateful we will of course uphold the constitution and obey the law".
Boris Johnson has warned he will call a snap election on the 14th of October if he loses this evening's vote.