Liz Truss is set to meet three more world leaders, including her Irish counterpart, as hundreds of dignitaries from across the globe descend on London to pay their respects to the Queen.
The talks may be casual, portrayed by No 10 as chats rather than formal bilateral sessions, but the Prime Minister’s meeting with Taoiseach Micheal Martin comes against a backdrop of political tensions over post-Brexit trading arrangements.
She had been due to meet US president Joe Biden, a milestone of her early premiership, but the talks were cancelled on Saturday, with a “full bilateral meeting” scheduled instead for Wednesday, when they are set to be in New York for the UN General Assembly.
In addition to Mr Martin, Ms Truss will meet Canadian prime minister Justin Trudeau and Polish president Andrzej Duda in Downing Street on Sunday.
The weekend’s talks with world leaders are being framed by No 10 as chats to offer condolences over the Queen’s death, during which politics is likely to come up.
Mr Martin has met Ms Truss in person briefly since she became Prime Minister earlier this month.
They were seated next to one another during a memorial service for the Queen at St Anne’s Cathedral in Belfast on Tuesday.
The meeting with Mr Martin comes as Britain is expected to push ahead with legislation to give ministers the power to scrap parts of the Northern Ireland Protocol, which was jointly agreed by the UK and EU in order to avoid a hard border on the island of Ireland.
Both the EU and Ireland claim Britain’s move to unilaterally revise the post-Brexit treaty would breach international law.
The issue is expected to ramp up ahead of a deadline at the end of October to form a new Northern Ireland Executive, which the DUP has so far blocked in protest over the protocol.
The PM kicked off her meetings with world leaders on Saturday, speaking to her counterparts from New Zealand and Australia.
The talks were held at the Government’s Chevening country residence, rather than Chequers, which is said to be undergoing routine maintenance work after Boris Johnson’s exit.
Ms Truss will also have an audience with the King at Buckingham Palace on Sunday, before attending his reception for visiting heads of state.
At 8pm, she will observe a minute’s silence with the country to mourn the Queen’s death and reflect on her life and legacy.
People have been invited to mark the occasion privately at home, on their doorstep or street, or at community events and vigils.