The parents of Harry Dunn have written to US President Donald Trump asking him to review the decision to block an extradition request for their son’s alleged killer.

The move was revealed after the PA news agency reported that lawyers acting on behalf of 42-year-old Anne Sacoolas had opened up a dialogue with the Foreign Office earlier this year to work towards a “resolution”.

Mr Dunn’s parents urged Mr Trump and US secretary of state Mike Pompeo to reconsider the decision to refuse the Home Office’s request to extradite Mrs Sacoolas, saying that facing the UK justice system would have “fairness at its heart”.

Charlotte Charles and Tim Dunn met the president at the White House six months ago, where he had hoped they would meet the suspect, who was waiting in a room next door, but they declined to see her.

They took their campaign for justice to the US in October, two months after Mr Dunn was killed when his motorbike collided with a car outside a US military base in Northamptonshire.

Mrs Sacoolas, the wife of a US intelligence official based at RAF Croughton, claimed diplomatic immunity following the crash and was able to return to her home country, sparking an international controversy.

She was charged with causing the death by dangerous driving of the 19-year-old in December but an extradition request was rejected by Mr Pompeo in January.

The Foreign Office has since come under fire after documents revealed a senior diplomat sent a text message to their US Embassy counterpart saying there was “not much mileage” in Mrs Sacoolas and her family staying in the UK, adding: “I think you should feel able to put them on the next flight out.”

Urging Mr Trump to reconsider the decision to refuse the extradition request, the teenager’s parents said: “It is now six months since we met with you, Mr President, in the Oval Office. We hope you are as well as can be in the current difficult circumstances.

“When we parted last October, you kindly mentioned that you would take a different look at the case and we have not heard from you since.

“We note from the British press that Mrs Sacoolas’ lawyer has reached out to the Foreign Office here in London and that she is attempting to seek a resolution to the problem. We understand that Mrs Sacoolas must be suffering too.

“The purpose of this letter is to ask you please to review your decision to not allow her to return to face the justice system, which as you know has fairness at its heart.

“As we are sure you can appreciate, it is really the only way forward in the interests of both families and of relations between our two nations which have suffered as a result of the decision.

“If you allow her to return, we are sure only good can come from it. Otherwise, the problem will never go away. No one is above the law.”

PA understands the letter has been acknowledged by a senior official at the White House.