After nearly a year of waffling, Britain on Monday finally opens negotiations with its European Union counterparts about leaving the bloc, with the final outcome, due in 2019, as important as it now seems unpredictable.
Anxious by immigration and loss of sovereignty, Britain voted past year to end its four-decades-old membership of the 28-country bloc - the first state ever to do so - in a shock referendum result.
Five of the UK's leading business organisations are calling for the government to maintain access to the Single Market and Customs Union until a Brexit deal is reached and to prioritise the rights of EU citizens in the UK.
Britain's negotiations with the European Union over its exit from the bloc begin on Monday and stand to be complicated by the surprise loss of Prime Minister Theresa May's parliamentary majority in a national election last week.
Poll finds majority support for a softer Brexit.
The government is due to present its legislative programme at the opening of parliament on Wednesday, which will be followed by a key confidence vote several days later. But the government will double the length of the session to let lawmakers debate Britain's approach to Brexit without interruption.
Subjects for the negotiations, which officially start in Brussels later, include the status of expats, the UK's "divorce bill" and the Northern Ireland border.
Brexiteers accept there is likely to be some short-term economic pain but say Britain will thrive in the longer term if cut loose from what they see as a doomed experiment in German-dominated unity and excessive debt-funded welfare spending.
Indeed, when it is taken into account that, in addition to the enormous bill which is looming, the United Kingdom electorate has never been asked to give a specific view on other vital issues, including the future of the single market, the customs union and the jurisdiction of European Court of Justice, a powerful case can be made for a second referendum on the validity of any final agreement.
Those issues are Britain's exit bill, estimated by Brussels at around 100 billion euros ($112 billion), the rights of three million European Union nationals living in Britain and one million Britons on the continent, and the status of the border between Northern Ireland and Ireland.
He vowed to seek "a deal that works in the best interests of all citizens" with Mr Barnier as the pair began discussions at the commission's Berlaymont headquarters in the Belgian capital.
Looking more sombre than his British counterpart, he said he hoped they could agree a format and timetable on Monday.
That source, and another in the Conservative party, said May's misjudged election gamble had undermined her authority, leaving her in the thrall of the two wings of her party that have differing views for Brexit - "purists" who want a clean break and "remainers" pressing for close ties. Hammond added that a worse outcome would be an arrangement in place that is punitive.
The chancellor said he would reject any deal "designed to destroy us".
VDMA managing director Thilo Brodtmann said in a statement that "the European Union and Great Britain must absolutely avoid being left without an agreement in two years".