The parents of Harry Dunn have arrived at the White House amid reports they are due to meet with Donald Trump about their son’s case.

The 19-year-old’s parents, Charlotte Charles and Tim Dunn, said they hoped the meeting would prove a “positive development” in their fight for justice.

Their campaign has attracted interest either side of the Atlantic due to the chief suspect being the wife of a US diplomat stationed in the UK.

Their teenage son was killed when his motorbike was involved in a head-on collision outside RAF Croughton in Northamptonshire in August.

Anne Sacoolas, the motorist allegedly responsible for the crash, was given diplomatic immunity and allowed to return to the US after the crash.

The family travelled to America earlier this week, and said they would be trying to convince President Trump to reverse the decision.

Harry Dunn
The family of 19-year-old Harry Dunn are heading to Washington for a meeting at the White House (Family Handout/PA)

In a post on the Justice 4 Harry GoFundMe page, Ms Charles and Mr Dunn said of the meeting at the White House: “We are grateful for the invitation, which we hope represents a positive development in our fight for justice.

“Our priority, as any parent will understand, is justice for our child. We believe this can only be achieved if Anne Sacoolas returns to England and engages properly with the justice system, where she will be treated fairly in a proper investigation of what happened to our son on that day – an investigation that cannot happen without her co-operation.

“Friends tell each other the truth. If Britain and America are friends then we believe there should be no possibility of a citizen of one country hiding from justice in another while falsely claiming a privilege such as diplomatic immunity.”

The family, who met Foreign Secretary Dominic Rabb in the UK last week, have also demanded an investigation over the Foreign Office’s (FCO) advice to Northamptonshire Police that Ms Sacoolas had diplomatic immunity.

They are demanding to see all emails, messages and notes sent in relation to her immunity status.

Speaking in New York, family spokesman Radd Seiger said: “We want to conduct an investigation into the FCO’s decision to advise Northamptonshire Police that this lady had the benefit of diplomatic immunity.

“What we don’t know is whether somebody cocked up or whether they were put under pressure by the Americans to concede.”

If they are not happy with the documents, the family say they will then ask for a judge’s opinion on the lawfulness of the FCO’s decision.

Harry Dunn death
A letter sent to the family by the Foreign and Commonwealth Office, explaining that the US suspect in the case of Harry’s death does not have diplomatic immunity (Family of Harry Dunn/PA)

Mr Seiger added: “If we’re not satisfied, then we’ll go to a judicial review and ask a High Court judge to review it all.”

On Saturday, before the family left for the US, they received a letter from Mr Raab, saying that Mrs Sacoolas, 42, no longer had immunity.

“The letter is worded very carefully, they’re not saying it’s just a change of heart – they are saying that it’s an evolution,” said Mr Seiger.

He also said that the family’s lawyers, Mark Stephens and Geoffrey Robertson QC, believe “they’ve (the FCO) been lying to you”.

Mrs Sacoolas has said she is “terribly sorry” about the incident and that she had “no time to react” when she saw Mr Dunn’s motorbike.