What could happen next in the Brexit saga?

With Brexit talks seemingly deadlocked and Prime Minister Boris Johnson seeking a rare Saturday sitting of MPs the day after next week’s crunch EU summit, here is a look at how events could unfold.

– Which are the key dates?

The UK is scheduled to exit the EU on October 31, Halloween, so the bloc’s heads of government summit in Brussels on October 17-18 will be key to efforts to secure a deal.

Government sources say the PM wants a rare Saturday sitting of Parliament on October 19 whether an exit deal is agreed or not.

– What happens if there is no deal?

Under the terms of the Benn Act, which the Commons passed against the PM’s wishes, the Government must ask Brussels for a three month Brexit extension if there is no deal by October 19.

– Would Downing Street do that?

The Government insists it will obey the law, but has also repeatedly stated the UK will quit the EU on October 31 with or without a deal.

There is also the possibility of a legal challenge to the Benn Act.

– Why does the Government want Parliament to sit on a Saturday?

Saturday October 19 is the day after the EU summit and is the trigger date for a Brexit extension request under the terms of the Benn Act if no agreement has been reached with Brussels.

If a deal is struck with the EU, MPs would be likely to debate it that day.

Downing Street is guarding its game plan closely, but there has been speculation that in the event of failing to reach agreement with the EU, Mr Johnson could press votes on issues like a no-deal exit, or a snap general election.

The Prime Minister cannot force Parliament to sit the extra day, MPs must give their approval for the Commons to meet on the Saturday proposed.

– Would the EU grant an extension request?

It is likely a Brexit delay would be approved, but all 27 remaining EU nations would have to sign up for the extension and they could insist on a shorter or longer duration than the one specified in the Benn Act.

– What is the problem preventing Mr Johnson and the EU cutting a deal?

As ever, the issue of the Northern Ireland border backstop looms large in the difficulties.

The PM wants to replace the backstop – the insurance policy against a hard border in Ireland – by keeping Northern Ireland in step with single market rules on goods, but taking it out, along with the rest of the UK, of the customs union.

The draft idea would mean some form of checks on goods to ensure the correct tariff was being paid.

The EU has rejected the initiative and is keen to stick to the border deal agreed by Theresa May.

Mr Johnson is expected to meet Irish premier Leo Varadkar on Thursday in a last-ditch effort to break the deadlock.

– Will there be an election?

The opposition has insisted it wants to ensure a Brexit extension before agreeing to Mr Johnson’s demand for an early poll.

Shadow Brexit secretary Sir Keir Starmer has said that a snap election would be “inevitable” if EU withdrawal is delayed.

There is also the possibility Mr Johnson could resign rather than be the PM to ask for an extension, setting himself up for what he could try and frame as a “people vs Parliament” election.

– What about a new referendum?

Such a move is possible, as some pro-Europeans, such as Labour deputy leader Tom Watson, want to separate Brexit from other issues.

However, a general election is more likely before any attempt at another Brexit poll.