MPs will be given the opportunity to vote on whether to hold a second referendum on Britain's membership of the European Union, Theresa May has announced.
The Prime Minister said the vote would be contained in the Withdrawal Agreement Bill, as she warned that a failure to reach an agreement on Brexit would lead to a "nightmare future of permanently polarised politics".
Speaking in central London, Mrs May outlined how her "new Brexit deal" differs to the previous deals rejected by Parliament – including a commitment in law to let Parliament decide on the customs issue.
She said: "I recognise the genuine and sincere strength of feeling across the House on this important issue.
"The Government will therefore include in the Withdrawal Agreement Bill at introduction a requirement to vote on whether to hold a second referendum and this must take place before the Withdrawal Agreement can be ratified."
Mrs May also told the audience at PWC in London that the Government would introduce a new Workers' Rights Bill to "ensure UK workers enjoy rights that are every bit as good as, or better than, those provided for by EU rules.
"And we will discuss further amendments with trade unions and businesses."
Mrs May said the deal sets out that the Government will seek to conclude Alternative Arrangements to replace the controversial Irish backstop by December 2020, "so that it never needs to be used".
Should it be used, she said the Government was committed to keeping Great Britain aligned with Northern Ireland.
MPs will have to approve the negotiating objects and final treaties for the UK's future relationship with the EU.
And Mrs May said there would be "no change in the level of environmental protection when we leave the EU".
She also pledged that the UK would seek "as close to frictionless trade in goods with the EU as possible" while outside the single market – while ending free movement.
And the UK will "keep up to date" with EU rules for goods and agri-food products that are relevant to checks at the border.
Mrs May said there would be a legal duty to secure changes to the political declaration to reflect the new deal.
In a plea to MPs, she concluded: "I say with conviction to every MP of every party – I have compromised. Now I ask you to compromise too.
"We have been given a clear instruction by the people we are supposed to represent.
"So help me find a way to honour that instruction, move our country and our politics forward, and build the better future that all of us want to see."