Theresa May heads to Canada on Monday to lay the foundations for a post-Brexit trade deal amid a ongoing furore over the Government's approach to withdrawal from the EU.
The Prime Minister was facing calls to sack Foreign Secretary Boris Johnson, who was branded a "backseat driver" by a cabinet colleague, after he set out his vision for a hard Brexit in a 4,000-word essay in the Daily Telegraph.
Mr Johnson's intervention, which led to a spat between him and the Chair of the UK Statistics Authority, came just days before a major speech in which Mrs May is expected to offer compromise.
A new trade deal between the EU and Canada is due to come into effect on Thursday, eliminating 98% of Canadian import duties, in what Downing Street describes as a "significant boon" for UK exporters.
But when Britain leaves the EU, it will fall out of the Comprehensive Economic and Trade Agreement (Ceta), which was championed by the UK and took seven years to negotiate.
Mrs May hopes to use Ceta as a model for a new bilateral arrangement between Britain and Canada to be introduced "swiftly" after Brexit.
Under the terms of its EU membership, the UK cannot seal a free trade agreement with an outside country before its departure, though it remains unclear whether this will be possible during the "transition period" expected to last two or three years after the official date of Brexit in March 2019.
The Prime Minister and her Canadian counterpart Justin Trudeau are expected to agree the establishment of a new joint working group, the 13th established by the UK since last year's referendum, to prepare the ground for a bilateral deal based on Ceta soon after Brexit.
Speaking ahead of her visit, Mrs May said that Canada and the UK form a "powerful union" when they work together on priorities like free trade.
"My visit to Canada is not only about recognising our past but also looking ahead to our bright future," she said.
"We are both countries with ambitions to lead on the world stage and progressive values that underpin those ambitions, values including the importance of free trade, and respect for international law.
"When we come together and work as one to project our shared values on the world stage, we form a powerful union."
The UK-Canada bilateral trade relationship is worth £15.2 billion annually and Britain is the second-biggest destination for Canadian investment abroad, with £1.75 billion invested since March alone.