PM signals he will push on with election plans as October 31 deadline in tatters

Boris Johnson has signalled he will push on with plans for a general election after his pledge to take Britain out of the EU by the end of this month was left in tatters.

The Prime Minister will introduce legislation for a poll on December 9 if his bid for an election three days later fails on Monday night, as is widely expected, a Number 10 source said.

Mr Johnson's election bid on Monday, to be made under the Fixed-Term Parliaments Act (FTPA), would require a two-thirds Commons majority – 434 MPs – to agree to an election on December 12.

But the Liberal Democrats and SNP have put forward a tightly-drafted Bill that would grant an election on December 9.

A Downing Street source said: "Tonight is Labour's last chance to have an election with Brexit done – they can vote tonight for the 12th and get Brexit done before Parliament is dissolved.

"If not, we will introduce a Bill almost identical to the SNP Bill tomorrow and we will have a pre-Christmas election anyway.

"This Parliament has repeatedly failed to respect its promise to respect the referendum.

"Millions of families and businesses can't plan because of constant delays. We need a new Parliament by Christmas so we can Get Brexit Done in January and the country can move on."

Lib Dem sources said they would need to see any Bill brought forward by the Government before deciding whether to support it.

One source said that it had to contain protection against a no-deal break, with the date of the election stipulated in the legislation.

"It is about making sure that Boris Johnson in some cunning fashion cannot engineer a situation where we crash out of the EU without a deal," the source said.

Earlier on Monday, Brussels accepted the UK's request for a so-called "flextension" until January 31 – enabling Britain to leave the bloc sooner if the Withdrawal Agreement Bill (WAB) becomes law.

Mr Johnson has previously said he would prefer to be "dead in a ditch" than miss the October 31 deadline.

European Council president Donald Tusk announced the decision following a meeting of ambassadors in Brussels.

He said: "The EU27 has agreed that it will accept the UK's request for a #Brexit flextension until 31 January 2020.

"The decision is expected to be formalised through a written procedure."

An EU source said the extension would last "only as long as necessary to allow for the ratification of the Withdrawal Agreement and, in any event, no longer than January 31 2020".

Britain would be able to leave the EU on the first day of the month following the ratification of the WAB by both the European and UK parliaments.

But the source added: "The United Kingdom will remain a member state until the new withdrawal date, with full rights and obligations, including the obligation to suggest a candidate for appointment as a member of the Commission.

"This extension excludes any re-opening of the Withdrawal Agreement."

The text will be submitted to the UK for agreement, before a written procedure is launched to adopt the decision – with the process likely to be concluded on Tuesday or Wednesday.