No budge on Brexit: The five options facing Theresa May
Theresa May survived a no-confidence vote in her leadership but her Brexit plans appear to have reached an impasse.
The arithmetic suggests her current blueprint will struggle to get a majority in the House of Commons, while EU leaders did not give the Conservative leader the assurances she hoped would help ease the passage of the bill.
What are the options now?
The EU changes its stance
The backstop in Ireland is the stickiest of sticking points - the EU says it will not drop it and Brexiteer MPs are refusing to support any deal which does not contain an exit clause.
European leaders said they would do their utmost so that the backstop - intended to ensure there is no return to a hard border between Northern Ireland and the Republic - would not be needed, but they insisted they could not re-open the terms of the Withdrawal Agreement.
But without a legally binding promise on the backstop, the doubters will remain.
Norway for now
A softer route to EU withdrawal, which was proposed by Tory backbencher Nick Boles and backed by some Labour MPs, would see the UK take on temporary membership of the European Economic Area (EEA) and European Free Trade Association (Efta) alongside countries like Norway and Iceland while a future trade deal is negotiated.
Efta membership would allow the UK to remain within a common market area with the EU and continue existing customs arrangements, while pulling out of common agricultural and fishing policies.
It would solve the border problem with Ireland, but critics say it would mean accepting freedom of movement for EU citizens.
The staunchest Brexiteers, like Jacob Rees-Mogg and John Redwood, say Britain has nothing to fear from EU withdrawal without a deal.
This would involve the UK falling back on World Trade Organisation rules which provide baseline requirements for tariff and customs arrangements between countries outside trading blocs like the EU.
Critics say this would result in high tariffs on many goods and exclusion from existing Europe-wide systems in areas like aviation, food safety and credit card payments, with a damaging impact on the UK economy.
But advocates of no deal insist the UK could offer low- or zero-tariff trade to partners and benefit from swift FTAs around the world while saving the £39 billion "divorce" payment to the EU.
Supporters of the People's Vote campaign want a referendum on any withdrawal deal - or no deal - with the option of remaining in the EU on the ballot paper.
They argue that voters in the 2016 referendum which delivered a 52-48 per cent majority for Leave did not have the full information about what Brexit would involve, and should have a chance to make a decision based on a clearer understanding of the terms on offer.
EU leaders have indicated they would be happy to accept Britain staying on as a member, and campaigners hope Brussels would be willing to put the Brexit process on hold to give time for a public vote to be held, probably in late spring.
Opponents of a second referendum warn that faith in democracy will be undermined if the Government does not deliver on the outcome of what was the UK's largest-ever ballot.
Extend Article 50
The letter which triggered the process for Britain leaving the EU was delivered on March 29, 2017, starting a two-year process of departure.
Mrs May alluded to the extension of Article 50 when faced with a vote of no-confidence, saying any successor's first job would be to delay Brexit, but any agreement to lengthen the process would have to be agreed unanimously.
Equally, the European Court of Justice ruled this week that Britain could rescind Article 50 if it wanted, however it is unclear whether Mrs May would receive political backing for such a move without taking the idea to the electorate.