Brexit: When will the UK actually leave the EU?

On 23 June, the UK voted to leave the European Union. Almost five months later, the country is still very much a part of the bloc.

Now a group of MPs say they will vote against triggering Article 50 of the Lisbon Treaty, the formal process for leaving. So, why is Brexit taking so long – and will it ever happen?

When will Brexit happen?

The short answer is: nobody knows. Prime Minister Theresa May said she will put Article 50 into motion by the end of March 2017. Assuming she is able to do so - and she may not be - the actual process of withdrawal must be completed within two years, according to the terms of the treaty. However, some believe the process could take longer, with extensions negotiable, says the Daily Telegraph.

Can May trigger Article 50 without parliament?

Only if she wins a Supreme Court appeal taking place next month. The Prime Minister had said that she could start the process of leaving the EU without a parliamentary vote. However, after campaigners launched a legal challenge, the High Court ruled last week that she couldn’t. The government has launched an appeal against this which will be heard by the Supreme Court over four days starting 5 December.

If the government loses, a bill will probably be put before parliament in the New Year, proposing the triggering of Article 50.

Could the Supreme Court decision stop Brexit?

If the judges find May needs to give parliament the chance to vote on whether to trigger Article 50, the Commons could, in theory, block the move. However, it seems highly unlikely MPs will risk overruling the result of the referendum, even though a majority are known to personally favour remaining in the EU.

Will any MPs vote against Brexit?

Labour and the Conservatives have pledged not to vote against leaving the EU, believing they must respect the decision made by the UK's voters. There will be some rebels, however. "Several" Labour MPs will vote against triggering Article 50, says the BBC, while the Lib Dems will oppose Brexit unless they are promised a second referendum on the terms of withdrawal. The SNP may well join them, while other Labour politicians may abstain.

What about the Lords?

Rebels in the Commons are "likely to embolden critics in the House of Lords", the BBC says. Labour and Lib Dem peers will try to amend the bill, joined by at least one Conservative colleague, Baroness Wheatcroft.

What about Scotland?

First Minister Nicola Sturgeon has repeatedly said she has a mandate to oppose Brexit because the referendum result north of the border was firmly in favour of remaining in the EU. Her government revealed this week it is trying to get involved in the Supreme Court case. 

Sturgeon says the consent of the Scottish parliament and other devolved assemblies should also be sought before Article 50 is triggered, the BBC reports. Scotland's highest legal official, the Lord Advocate, has applied to be heard in the case next month.