The prime minister will join the King at the formal opening of the Commonwealth Heads of Government Meeting in Antigua later – and begin talks with fellow leaders about the UK issuing a formal apology for the slave trade in the next year.

As part of the discussions, Downing Street said Andy Burnham would set out his plans for what it is calling a “debt reset” to support Commonwealth countries having to deal with the growing costs of paying interest on their debts.

The issue of reparations, compensation to those who were the victims of slavery, has dominated debate in the build up to this summit, in which representatives from 56 Commonwealth countries are meeting.

“Britain is bringing a new approach to this meeting,” the prime minister said, in a tacit acknowledgement that the last Commonwealth gathering, on the Pacific island of Samoa two years ago, did not go well from a UK perspective.

The previous Prime Minister Sir Keir Starmer had said prior to the meeting that reparations were not on the agenda, but other leaders insisted they should be.

This time, the new prime minister has sought to get ahead of the debate, and appeared to directly address the anger of some Commonwealth leaders after the last summit.

“For years, those members of the Commonwealth affected by the slave trade have asked for an honest conversation about the legacies of slavery, external. By sticking our heads in the sand, we have damaged the ability of the Commonwealth to function,” Burnham argued in an article in the Guardian.

Burnham alongside the Foreign Secretary Ed Miliband and the former Prime Minister Gordon Brown, are beginning conversations which, they hope, will help detoxify the debate about reparations.

They do so while insisting the UK will not pay them, but is likely to formally apologise for the slave trade for the first time next year, when the UK holds the rotating presidency of the G20 group of countries.

“A formal apology,” Miliband said in a social media video, external, is something “the British government are open to”.

He said this would be a “significant step” but added that “we don’t believe financial reparations are the right or feasible answer to transatlantic slavery. We don’t think the right response is to ask British taxpayers today to make financial payments for these historic acts.”

The Conservative leader Kemi Badenoch has urged the prime minister not to issue an apology for slavery, saying it would give countries a reason to ask the UK for reparations.

She said: “I don’t think we should be giving any money to compensate people for the slave trade, and I don’t think that Andy Burnham needs to be apologising because it is a lever to wedge open the door to ask for cash.”

But British officials are hopeful, even confident, that the prime minister and foreign secretary’s approach will create space in the next two days for a wider conversation with fellow Commonwealth countries.

No 10 said the UK would lead two new task forces – one focused on critical mineral assets and vulnerabilities in supply chains across the group and the other aimed at boosting trade and investment more widely.

Both will be set up by the end of the year and report back at the next leaders’ summit, officials said.

British diplomats view the Commonwealth as a useful forum for conversations with developing countries, and, crucially, one that does not involve China, America or Russia.

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