- Video report from ITV News Political Correspondent Daniel Hewitt
Brexit Secretary David Davis will call for a "deal like no other in history" as he sets off for Brussels to launch negotiations for Britain's divorce from the European Union.
Formal talks to agree a host of issues around the terms of the UK's departure from the bloc will begin on Monday, almost a year to the day after the referendum vote to leave.
But there is still disagreement about exactly what Brexit will look like after the Conservative's poor performance in an election they largely portrayed as a vote of confidence on Theresa May's plans for a hard exit.
The Chancellor Philip Hammond weighed into the debate on Sunday, as he said that the Government is sticking to its plans to leave both the single market and customs union.
In a slight softening of tone, he said that failing to secure a deal from EU officials would be "very, very bad" for the country and insisted there must be transitional arrangements to avoid a "cliff edge".
Some MPs within the Conservatives are now pressing the Prime Minister to pursue a softer Brexit.
Meanwhile Labour leader Jeremy Corbyn said it would leave the single market but remain in the customs union if they were in charge of the deal.
Mr Davis will be accompanied to Brussels for the talks by a nine-strong negotiating team.
It includes the most senior civil servants at the department as well as officials from the Treasury and Home Office as well as Mark Sedwill, the national security adviser to the Prime Minister.
As he sets off, the Brexit Secretary is expected to say the negotiations will "shape the future of the European Union and the United Kingdom, and the lives of our citizens".
The talks are likely to be unprecedented in complexity as officials get to grips with unmeshing a relationship that goes back 40 years and covers a host of issues and laws.
Both sides are still in disagreement over how exactly they will progress.
The UK wants to begin working out the details of a trade agreement alongside the terms of the withdrawal process.
However, Europe says that an agreement on issues such as the rights of citizens, the divorce bill and border controls must come before considering any post-Brexit settlement.