The Liberal Democrat leader, Ed Davey, has called for a national debate over Britain’s role in the slave trade, after the coronation reignited questions over the monarchy’s historical links. He said he wanted a “more open-minded approach” to dealing with questions over the UK’s role in enslaving Africans, praising the path taken by the New Zealand government, which has offered an apology and more than $150m in reparations to Indigenous communities for past mistreatment. Davey told the BBC’s Laura Kuenssberg on Sunday: “We really want a much more open-minded approach … We should have a debate about this. And in the context of Britain’s relationship with the world – not just with our Commonwealth partners, but with the rest of the world – I really think just closing the debate down is not the way forward.” Davey’s comments come after King Charles signalled his support for research into the royal family’s links with the slave trade. Buckingham Palace said last month it was supporting a research project into the monarchy’s centuries-long links with slavery, after the Guardian published a previously unseen document showing that the slave-trading Royal African Company transferred £1,000-worth of shares to King William III in 1689. The king was keen to make his coronation on Saturday a multicultural event, giving prominent roles to black and ethnic minority Britons and being greeted as he left Westminster Abbey by representatives of the Jewish, Muslim, Sikh, Hindu and Buddhist communities. But he remains under pressure to issue a formal apology for slavery and empire, with Indigenous groups from 12 Commonwealth countries calling on him to “acknowledge the horrific impacts on and legacy of genocide and colonisation of the Indigenous and enslaved peoples”. Rishi Sunak has ruled out his government making an apology or reparations for slavery. The prime minister told the Commons last month: “Trying to unpick our history is not the right way forward, and it’s not something that we will focus our energies on.” Those comments dismayed some Commonwealth leaders, with Johnny Briceño, the prime minister of Belize, telling the Guardian this week:” “I think [Sunak] has a moral responsibility to be able to offer at the very least an apology.” Davey said on Sunday: “The king is moving towards trying to look at this issue with greater subtlety than we’re seeing from the government.” He praised the approach taken by New Zealand, where the former prime minister Jacinda Ardern offered an apology and $155m in reparations on behalf of the British crown to a Māori tribe for previous battles over Māori land. Chris Hipkins, her successor, told the BBC on Sunday: “When you look into the past and identify what’s happened – in many cases horrific and horrible things have happened – making a record of that and then acknowledging it and finding a way of providing some redress is a very, very powerful thing.”