Rishi Sunak has revealed he will personally invite US president Joe Biden to visit Northern Ireland next month to mark the 25th anniversary of the Good Friday agreement. In the biggest hint yet that the much-anticipated trip will go ahead, the prime minister told reporters on the plane to a summit in California that he hoped Biden would be able to make it. Having dealt with the tricky issue of the post-Brexit Northern Ireland protocol, which many in Washington viewed as vital to such a trip getting the green light, Sunak stressed there was an opportunity to “celebrate” the peace that followed the agreement. He said: “I’ll be keen to invite [Biden] to come. It’s not confirmed yet. But it will be something that obviously I’ll be talking to him about. Hopefully he will be able to make it.” Sunak said a visit by the US president would be “a nice way” to mark the anniversary of the Good Friday agreement, with a host of other politicians – including Bill and Hillary Clinton – expected in Belfast for a large event on 17-19 April, organised by Queen’s University. The anniversary falls on 10 April, and marks 25 years since the day an agreement was reached by the former British and Irish prime ministers Tony Blair and Bertie Ahern, as well as the former US senator George Mitchell. Biden, who has Irish heritage, is already said to have sent “pre-advance” teams from the White House to Belfast and to the Republic of Ireland for initial assessments on security and policy matters to be discussed on the trip. Sunak highlighted his recent breakthrough on the Northern Ireland protocol – overhauled in a pact with the EU known as the “Windsor framework”, calling it a “positive step”. “I was very keen to try and bring resolution to some of the challenges of the protocol and … do the right thing for the people and businesses there,” he said. Asked if the UK-US “special relationship” would be boosted by another visit to Britain in May for King Charles’s coronation, Sunak did not rule out the possibility. “There’s lots of great things to celebrate,” he said, but stressed there had been no decisions taken.