Lawyers representing the family of 19-year-old motorcyclist Harry Dunn are poised to receive a series of crucial documents which they believe will help their legal case to expose a “scandalous cover-up” by the Foreign Office. The development comes after documents showed that a senior Foreign Office diplomat had sent a text message to a US Embassy counterpart saying they should “feel able” to put suspect Anne Sacoolas on the next flight back to the States. Dunn died in August last year when his motorcycle collided with a car driven by Sacoolas, the wife of a US intelligence officer stationed at a US 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. However, she was then controversially allowed to leave the country a fortnight later, claiming diplomatic immunity. On Thursday, Dunn’s family learned that the US authorities had rejected their appeal to Donald Trump to reconsider his refusal to send her back to the UK. The family is now seeking a judicial review into the handling of the case. Yesterday, the family’s spokesman, Radd Seiger, said that a court order instructing the Foreign Office to supply documents had been breached, a claim denied by the department. Initial disclosure documents have already revealed that an internal briefing note sent three days after the fatal crash – copied to the private secretary of Dominic Raab, the foreign secretary – revealed concern for some “very unpalatable headlines”. Further UK government documents will reportedly be disclosed to the family’s lawyers this week. Seiger told the Press Association: “Frankly, Raab’s conduct in the judicial review has been nothing short of disgraceful.” The Foreign Office said: “We are responding to legal action in the judicial review in the normal way and have responded to all the court requirements in full.”