The Commonwealth's 56 members agreed the "time has come" for talks about the legacy of the "abhorrent" transatlantic slave trade on Saturday, in a landmark summit declaration that raised the prospect of future reparations.

Gathering in Samoa, leaders from Britain and dozens of former colonies held lengthy and occasionally tense talks over one of the most sensitive aspects of their shared and troubled past.

In a joint statement, Commonwealth leaders noted calls for "reparatory justice" for the "abhorrent" transatlantic slave trade and the "enduring effects" of dispossessing Indigenous people, indentureship and colonialism.

"The time has come for a meaningful, truthful and respectful conversation towards forging a common future based on equity," a joint "Samoa Communique" said.

African, Caribbean and Pacific nations want Britain — and other colonial powers — to atone for slavery and other ills of colonisation, and to start talks about compensation.

Many remain poorer than their one-time colonial masters and are still scarred by the brutal trade that saw an estimated 10-15 million enslaved people ripped from Africa over four centuries.

While Britain has expressed remorse for slavery in broad terms, London has baulked at the idea of paying financial reparations, which could come with a hefty price tag.

During the summit, London tried to avoid making explicit commitments while trying to retain some semblance of Commonwealth unity.

"I should be really clear here, in the two days we've been here, none of the discussions have been about money", British Prime Minister Keir Starmer said after the meeting.

"Our position is very, very clear in relation to that", he said, insisting talks had been "very positive".

The meeting's conclusion was delayed for hours as leaders and officials tried to hammer out a compromise.

The final text may be more vague and legalistic than some former colonies wanted.

During the summit, Bahamas Prime Minister Philip Davis told AFP it was time for "a real dialogue about how we address these historical wrongs".

"The horrors of slavery left a deep, generational wound in our communities, and the fight for justice and reparatory justice is far from over."

But one expert said the summit could come to be seen as historic.

"The commitment to conversations on reparatory justice wedges open the door for dialogue," said Kingsley Abbott, of the University of London's Institute of Commonwealth Studies.

"The Commonwealth", he said, "should see this as an opportunity to lead on a potentially historic process, and to do so with vision and courage."

'Painful' past 

For Britain — still staking out its place in the world after empire and leaving the European Union — the summit was a high-stakes balancing act.

Starmer is under political pressure at home, and King Charles III, whose family benefited from the slave trade over centuries, had faced calls to apologise personally.

The British royal, who was attending his first summit as monarch and as head of the Commonwealth, stopped well short of an apology on Friday, asking delegates to "reject the language of division".

"I understand, from listening to people across the Commonwealth, how the most painful aspects of our past continue to resonate," he said.

"None of us can change the past. But we can commit, with all our hearts, to learning its lessons and to finding creative ways to right inequalities that endure."

Charles left to return to London before the final summit communique had been agreed.

Blue Pacific

Commonwealth leaders found more common cause on the "existential" issue of climate change.

They agreed to an "Ocean Declaration", which recognises current national maritime boundaries even if sea levels continue to rise.

They also agreed to protect at least 30% of the ocean and to restore at least 30% of degraded marine ecosystems by 2030.

"What the ocean declaration seems to do and to say is that once your marine boundaries are fixed, they are fixed in perpetuity," outgoing Commonwealth Secretary-General Baroness Patricia Scotland told AFP.

Commonwealth leaders also agreed to name Ghana's foreign minister Shirley Ayorkor Botchwey as the new secretary-general.

A former lawmaker, she has served as foreign minister for the past seven years, notably steering Ghana's two-year tenure on the UN Security Council, ending in December 2023.

She has backed the drafting of a Commonwealth free trade agreement and has previously said she stands for reparations.

"Truly humbled by the overwhelming support of the Commonwealth Heads of Government in selecting me as the incoming Secretary-General of the Commonwealth", she posted on social media.

"The work indeed lies ahead!"