Delaying Britain’s final departure from the European Union has been floated as a way of helping break the deadlock in Brexit talks.

Here we look at what it would mean:

– When would Britain leave under the proposals?

Prime Minister Theresa May insisted any extension to the transition period would only last “a matter of months” after a furious Tory backlash. It would mean staying in the single market and customs union and being subject to EU rules beyond the scheduled end-date of December 2020.

– Why are Conservative MPs so angry?

They say that any extension would leave Britain bound by EU rules and facing a big extra bill as the EU would be entering a new budget period and the UK would have to contribute. That would cost up to £18 billion a year, according to former Tory minister Nick Boles. He says Conservatives are “close to despair” over how the negotiations are going.

– Would extending the transition period solve the deadlock?

It is hard to see how. The deadlock in the talks centres on having a backstop policy to deal with the Irish border if Britain leaves without another solution having been found, but that would need to be agreed in the divorce deal that must be signed off in the next few months.

– What happens next?

If progress had been made at the European Council meeting of leaders, an extra summit was expected to be held in November to sign off the deal. EU chief Brexit negotiator Michel Barnier could still call an emergency meeting next month but the next gathering in the diary is in December.