Donald Trump has told Boris Johnson they can "work together to find a way forward" over a US woman allegedly involved in the death of a British teenager.
The leaders spoke in a phone call tonight, according to Number 10.
It came hours after Harry Dunn's parents revealed that they will travel to Washington to launch legal action against car crash suspect Anne Sacoolas..
Charlotte Charles and Tim Dunn, whose son Harry Dunn was killed in an accident in Northamptonshire on 27 August, will make the trip in the coming days following a "disappointing" meeting with Foreign Secretary Dominic Raab.
Mrs Sacoolas, 42, was granted diplomatic immunity there after flying back shortly after the fatal crash.
Police believe she pulled out on the wrong side of the road as she emerged from US spy base RAF Croughton, and collided with Harry Dunn, 19, as he rode his motorbike – causing fatal injuries.
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Speaking after the 45 minute-long discussion with the foreign secretary, Mr Seiger said: "To say we are disappointed with the outcome of the meeting would be an understatement."
He told Sky News the family felt the "strange" meeting was poorly handled, and that it had left them feeling "perplexed, angry and confused".
The family said they felt the meeting had been a "publicity stunt" and they were "disgusted".
Mr Raab is said to have relayed the steadfast US position on the issue, which is that the White House will not consider granting any waivers of diplomatic immunity.
He had previously urged Washington to reconsider its position and "do the right thing by Harry Dunn's family", after meeting the US ambassador on Tuesday.
Mr Seiger told Sky News the family was "disappointed" by the US stance, adding: "These parents are determined to seek justice for Harry and they can do anything they can to achieve those ends."
He later told reporters that the family plans to recruit lawyers in the UK and the US with a view to possibly filing a civil claim against Mrs Sacoolas.
Ms Charles has also made a direct appeal to Mrs Sacoolas to return, telling reporters: "Do the humane thing, get on the plane and come back – from one parent to another.
"How would a human make a decision to get on a plane and run away from what she's done and try and continue her life, what kind of example is she setting to her children? She's being dishonest by running away from us."