Prime Minister Theresa May is holding consultations with party leaders and other senior MPs representing the various strands of opinion in the Commons in an attempt to find a way forward on Brexit.
These are the main parties and cross-party groupings at Westminster:
The Government: Theresa May says she wants a deal that gives the UK control of its money, its laws and its borders, protects the Union and enables it to pursue an independent trade policy – effectively ruling out a customs union. Has repeatedly rejected calls for a second referendum, an extension to the Article 50 withdrawal process or to rule out no-deal.
Labour Party: Labour wants a deal based on a new customs union with the EU, a close relationship with the single market and protection of workers’ rights and the environment. Jeremy Corbyn says he will not meet Mrs May unless she takes no-deal off the table. Party policy allows for a second referendum but Mr Corbyn has been reluctant to call for one, despite strong support from MPs and activists.
SNP: Opposes Brexit. Says the options of ruling out no-deal, extending Article 50 and staging a second referendum must all be on the table if there is to be any further negotiation.
DUP: Strongly pro-Brexit. The party, which props up the Government in the Commons, says the Northern Ireland backstop must go if it is to support any agreement.
Liberal Democrats: Oppose Brexit. Their key demands are a second referendum and taking no-deal off the table. Party leader Sir Vince Cable has said he is prepared to carry on talking.
European Research Group: Strongly pro-Brexit group of Tory MPs led by Jacob Rees-Mogg. Favours a looser Canada-style free trade agreement but many members woule be content to see a no-deal Brexit if that proves impossible. Strongly opposed to any extension of Article 50 and insists the backstop must go.
Norway Plus: A loose cross-party grouping of mainly Remain-supporting MPs – including Conservative Nick Boles and Labour’s Stephen Kinnock – who want a closer future relationship with the EU based on a customs union and membership of the European Free Trade Area, along with Norway, Iceland and Liechtenstein.
People’s Vote: A pro-Remain cross-party campaign in support of a second referendum. Backed by almost 100 Labour MPs as well as the Greens, Plaid Cymru and a handful of Conservatives such as Anna Soubry.