Boris Johnson has promised to raise Rwanda genocide suspects living in Britain with the Metropolitan Police amid anger over delays to justice.

The Prime Minister on Friday suggested that he made the pledge to Rwandan President Paul Kagame when they met in the capital of Kigali this week.

Scotland Yard is investigating five individuals living in the UK after a referral from Rwanda over allegations to the 1994 genocide.

Hutu extremists slaughtered an estimated 800,000 Rwandans, mostly Tutsis but moderate Hutus too, during 100 days of the civil war.

Commonwealth Heads of Government MeetingPrime Minister Boris Johnson speaks at a press conference (Dan Kitwood/PA)

Mr Johnson came under pressure from a journalist for a Rwandan publication at a press conference in Kigali, who warned that justice delayed is justice denied and reminded that genocide is a crime against humanity.

“I went to the genocide memorial yesterday and nobody could go there without being absolutely harrowed by what happened here, in Rwanda, I understand people’s feelings,” the Prime Minister responded.

“So what I said to President Kagame yesterday is I will do everything I can to try to expedite this.

“It is in the hands of the Metropolitan Police, I can’t intervene directly, but I will certainly be raising it with them and I understand why people in Rwanda feel as you do.”

Mr Johnson visited the Kigali Genocide Memorial, where the remains of an estimated 250,000 people are interred, after his meeting with Mr Kagame on Thursday.

The Prime Minister, who was in the city to attend a Commonwealth leaders’ summit, wrote in the visitors’ book that he found the visit “utterly shocking”.

“We must do everything we can to ensure that human hearts never again are allowed to breed such hatred,” he added.

Commonwealth Heads of Government MeetingPrime Minister Boris Johnson visits the Kigali Genocide Memorial (dan Kitwood/PA)

The issue is intensely personal for Mr Kagame, having played a key role in seizing Kigali to end the genocide.

Scotland Yard’s war crimes unit is investigating after receiving the referral from Rwanda in January 2018.

In July 2017 the five suspects had an extradition bid to have them returned to Rwanda blocked by the UK High Court.

At the time judges agreed there was a real risk they would be denied a fair trial if they were returned.

Mr Kagame’s regime is accused of political repression and the detention of critics.