The parents of Harry Dunn have urged the Foreign Secretary to concede his department’s position on the diplomatic immunity claimed by their son’s alleged killer.

Charlotte Charles and Tim Dunn wrote to Dominic Raab on Monday to invite him to seek an “urgent declaration” from the High Court that 42-year-old Anne Sacoolas did not have immunity at the time the 19-year-old was killed in a road crash.

An urgent declaration from the High Court would bring to an end the judical review proceedings against the Foreign Office (FCO) in which the family are seeking an order quashing the FCO’s alleged decision to advise Northamptonshire Police that Mrs Sacoolas had immunity”.

The teenager’s parents also called on Mr Raab to withdraw his statement to the House of Commons on October 21 last year in which he stated Mrs Sacoolas had diplomatic immunity – describing it as “misleading”.

Harry Dunn death
Harry Dunn’s mother Charlotte Charles, alongside his father Tim Dunn, wrote to the Foreign Secretary on Monday (Aaron Chown/PA)

The move comes in the week in which the family’s lawyers are expected to receive further disclosure documents which they hope will assist them in their judicial review claim against the FCO.

A spokesman for the FCO said neither they nor Northamptonshire Police could have “legally prevented” Mrs Sacoolas from leaving the UK.

It is understood the Foreign Office is confident they have acted properly and lawfully in relation to Mr Dunn’s death.

The teenager was killed when his motorbike crashed into a car outside a US military base in Northamptonshire in August last year.

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 death by dangerous driving in December but an extradition request for Mrs Sacoolas, submitted by the Home Office, was rejected by US secretary of state Mike Pompeo in January.

Previous disclosure documents, seen by the PA news agency, showed that a senior diplomat at the FCO had sent a text message to their US embassy counterpart saying they should “feel able” to put the suspect on the next flight home.

The material, which surfaced earlier this year, also showed a briefing note copied to Mr Raab’s private secretary from three days after the fatal crash which revealed concern for some “very unpalatable headlines”.

Speaking on behalf of the family after the letter was sent to the Foreign Secretary, their spokesman Radd Seiger told PA: “It is now time the UK Government put the interests of its citizens above anything else.

“Anne Sacoolas never had diplomatic immunity, yet the UK Government rolled over under pressure from the US government and agreed that she did, unlawfully.

“Mr Raab misled Parliament when he spoke in the House of Commons on October 21 and he must now withdraw that statement and I have invited him to do so.

“We cannot bring Harry back. But we can help alleviate some of their suffering by ensuring they get the justice they deserve, that every single one of us are entitled to.

“Mr Raab must now urgently seek an order from the High Court in London that Anne Sacoolas did not have diplomatic immunity, then formally demand that the US Government return her to face justice.”

Responding to the family’s requests, a spokesman for the FCO said: “As the Foreign Secretary set out in Parliament, Anne Sacoolas had diplomatic immunity while in the country under the Vienna Convention on Diplomatic Relations.

“The decision to withdraw the family was taken by the US. The FCO consistently called for Anne Sacoolas’ immunity to be waived, but neither the FCO nor the police could have lawfully prevented her leaving the UK.

“The Prime Minister and Foreign Secretary have been clear with the US that their refusal to extradite Anne Sacoolas amounts to a denial of justice and she should return to the UK.”