Anna Sacoolas with her husband

The US Secretary of State’s decision to deny the extradition request of Anne Sacoolas, a suspect in the death of Harry Dunn, has been described as a “denial of justice” by the Home Office.

Mike Pompeo’s decision was passed to the 19-year-old’s parents yesterday in a phone call with their constituency MP, Andrea Leadsom. A spokesperson for the family said that the US government was “behaving lawlessly”.

Mrs Leadsom will today meet with the US ambassador, Woody Johnson, to discuss the case. The Foreign Secretary, Dominic Raab, said the “UK would have acted differently” and that he expressed the British government’s disappointment in a phone call with Johnson earlier today.

In December, the Crown Prosecution Service charged Sacoolas, 42, with causing Dunn’s death by dangerous driving. He was killed outside a US military base in Croughton, Northamptonshire. Sacoolas claimed diplomatic immunity and returned to the US following the incident.

Controversy has arisen from disagreements around Sacoolas’ eligibility to claim diplomatic immunity. Lawyers for the Dunn family have argued that her claim is not valid, with their spokesman Radd Seiger describing their refusal to extradite as “taking a wrecking ball to one of the greatest alliances in the world”.

This marks the first time since the UK-US extradition treaty of 2003 that the US has denied a request made by the UK. A spokesperson said that granting the request would effectively nullify diplomatic immunity, while expressing the State Department’s sympathy for the Dunn family.

The Dunn family was invited to the White House in October during an American press tour, where they say they were urged three times by Donald Trump to meet with Sacoolas, whom they had not known would be waiting in the next room.

“We had it sprung on us that she was there,” said his mother, Charlotte Charles. “We were not impressed.”

Mr Dunn’s parents have stated their willingness to meet with Sacoolas, though only on British soil and in the presence of lawyers.

Following the extradition refusal, Mr Seiger said: “We’ll simply take it in our stride. Everybody’s relaxed, we knew this day was coming,” adding that “the fight goes on” to secure justice for Mr Dunn. The family is expecting to hear from Mrs Leadsom details of what she discusses later today with Ambassador Johnson.