The Foreign Office has obstructed a search for truth into the death of 19-year-old motorcyclist Harry Dunn, lawyers for his family have claimed prior to a potentially tense meeting with aides to Dominic Raab, the foreign secretary. Dunn died in August when his motorcycle collided with a car driven by Anne Sacoolas, the wife of a US intelligence officer stationed at a US spy base at RAF Croughton, Northamptonshire. Sacoolas immediately admitted to the police she had caused the accident by driving on the wrong side of the road. She then left the country a fortnight later claiming diplomatic immunity. The US government has rejected a Home Office request for her to return to the UK to stand trial. The family had also written to Donald Trump urging him to reconsider his refusal to send her back to the UK, but the US government on Thursday again rejected the plea. Downing Street insists it backed the Dunn campaign to persuade Sacoolas to return to face UK courts and had objected to her departure every step of the way. But the family’s lawyers, after leaks of internal memos and evidence given to the foreign affairs select committee, believe they were misled. The UK shadow foreign secretary, Lisa Nandy, has called for a parliamentary inquiry into how the family were treated. It is understood that Keir Starmer, the Labour leader and former director of public prosecutions, is also taking an interest. The family is seeking a judicial review into the handling of the case, which could reveal if there were any conflicting currents within the Foreign Office over whether to resist the US view that she was covered by diplomatic immunity. Any court hearing might also reveal exchanges between the Northamptonshire police and the Foreign Office over the degree of discretion the police had to arrest and prosecute Sacoolas, even if the Foreign Office (FCO) told the police she had diplomatic immunity. Radd Seiger, the lawyer for the Dunn family, said he would be demanding the truth at Friday’s meeting: “The foreign secretary has stated in each of our meetings with him that the FCO fought to keep Mrs Sacoolas here. “The FCO’s initial position, like ours, was that Mrs Sacoolas did not have diplomatic immunity. So why did they cave in on this interpretation of the law in a matter of three working days? To make matters worse, they failed to pass any of this to Northants police, who were kept totally in the dark for 14 days when it was their job to establish whether she had immunity or not. Shockingly, the police were not told anything until the day after Mrs Sacoolas left, depriving them of their ability to investigate matters.” Sacoolas left the UK on 15 September after the Foreign Office agreed she had diplomatic immunity, and the US refused to waive it. Internal memos suggest the Foreign Office decided she had immunity, a complex point of law, within a week of Dunn’s death. Seiger’s argument turns on exchanges between the Foreign Office and the US State Department in the immediate wake of the crash that led to Foreign Office lawyers concluding she did have diplomatic immunity, he says. The Foreign Office negotiated a treaty with the US and the UK that waived immunity for US staff at the Croughton base, but the treaty was silent on the status of the staff’s dependants, such as Sacoolas, leading the US to argue she had immunity. A Foreign Office spokesperson said: “We have deep sympathy for Harry’s family. We have done and will continue to do everything we properly can to ensure that justice is done. “As the foreign secretary set out in parliament, Anne Sacoolas had diplomatic immunity whilst in the country under the Vienna convention on diplomatic relations. “We consistently called for Anne Sacoolas’s immunity to be waived before she left the UK. Both the prime minister and the foreign secretary have been clear with the US that the refusal to extradite her amounts to a denial of justice, and that she should return to the UK.”