Britain's opposition Labour Party was to on Monday demand that parliament has the final say on the government's Brexit deal, including an option to send ministers back to the negotiating table rather than leave without an exit agreement.

After reaching a deal last week on a transitional period lasting until the end of 2020, Prime Minister Theresa May's team must now set about negotiating Britain's long-term trading arrangements with the European Union — perhaps the hardest stage yet in the complicated divorce talks.

The government has promised to put that final deal to parliament for approval, but has made clear the choice is either to accept the exit agreement, or leave without a deal.