Caribbean countries are considering approaching the UN’s international court of justice (ICJ) for a legal opinion on demanding compensation from 10 European countries over slavery, as the fight for reparative justice is stepped up, the president of the group of 33 nations in the region has said. Ralph Gonsalves, the current leader of the Community of Latin American and Caribbean States (Celac), said he was also looking for an apology from the British government and expressed disappointment in Rishi Sunak’s lack of engagement in the matter. “I’m disappointed to see that Sunak, who ought to, given his origins, have a greater sensitivity to this question of the past,” said Gonsalves, who has been prime minister of St Vincent and the Grenadines for 22 years. Sunak’s parents were of Indian origin and raised in British colonies in east Africa. “I’d like an apology from the British government and the engagement for a mature conversation for a programme for reparatory justice,” Gonsalves said. He said reparative justice was not just a crude calculation about monetary compensation for descendants of enslaved people but a wider recognition of the continuing effects of slavery and colonisation on public health, economic development and cultural heritage. He failed to persuade the EU leaders at a summit with the Celac leaders in Brussels to include a paragraph in an official communique recognising native genocide, the elimination of Indigenous peoples through colonisation. But he said he accepted that not all European countries were involved in colonisation. “This is not a case of looking for people with the DNA who were enslaved. No, we are dealing with the historical legacies of the enslavement of [Africans] and there are contemporary manifestations on the development linked directly to slavery and indeed, to native genocide,” he said. Separately, the Caribbean Community has already developed a 10-point plan for reparatory justice, which ranges from demands for full formal apologies from slaver nations to a recognition of native genocide and debt cancellation. They also want recognition that the Africa-descended population “has the highest incidence in the world of chronic diseases”, including hypertension and type 2 diabetes, something they believe is part of the “stress profiles associated with slavery”. Asked if he thought European countries were taking the issue of slavery seriously enough he replied “yes” but said time would tell. “Sometimes, a person may take something seriously with words, but it may take a little while for you to know whether it’s a noise in the blood and an echo in their bones. And we will wait to see how that happens,” he said. Last month the Dutch king apologised for his country’s role in slavery. Gonsalves said a decision on a formal approach to the ICJ to receive a legal advisory would probably be taken in August at a meeting of a prime ministerial subcommittee on reparations of the Caribbean countries in August led by the Barbados prime minister, Mia Mottley. “This is a very serious matter,” said Gonsalves. “We have had some legal work done already prepared,” he added, saying the issue was gaining “more and more traction” in Europe. “We are at the stage where we probably will go to the international court of justice for an advisory opinion, but there are other parallel activities which are taking place and this is gathering momentum,” he told the Guardian in Brussels. A legal advisory from the ICJ is not legally binding but would put pressure on the 10 European countries targeted to engage in reparative justice. “Despite having no binding force, the court’s advisory opinions nevertheless carry great legal weight and moral authority. They are often an instrument of preventive diplomacy and help to keep the peace. In their own way, advisory opinions also contribute to the clarification and development of international law and thereby to the strengthening of peaceful relations between states,” the ICJ’s website says. Gonsalves said the time had come for “a mature conversation” with the likes of France over damage in Haiti, the Netherlands in Suriname, and Spain’s history with many Latin American countries over their past wrongs. “People used to say only people on the fringes spoke about this but now the subject is in the mainstream,” he said. “Remember the resources from the slave trade and slavery helped to fuel the Industrial Revolution and laid the basis for a lot of wealth in western Europe.”