Harry Dunn's alleged killer Anne Sacoolas was never entitled to diplomatic immunity while her husband was working at an RAF airbase, the High Court has heard.
Lawyers representing Mr Dunn's family say a 1995 waiver agreed between the US and UK meant administrative and technical staff at RAF Croughton did not have diplomatic immunity beyond their duties.
Mr Dunn, 19, was killed when his motorbike crashed into a car being driven on the wrong side of the road by American Anne Sacoolas outside RAF Croughton in Northamptonshire on August 27 last year.
Sacoolas, whose husband Jonathan Sacoolas worked as a technical assistant at the base, left the country a few weeks later after the US said she was entitled to diplomatic immunity.
But Sam Wordsworth QC, representing Mr Dunn's family, has today declared Sacoolas 'never had any relevant immunity'.
The 43-year-old was ultimately charged with causing death by dangerous driving last December, but an extradition request was rejected by the US State Department in January - a decision it later described as 'final'.
Documents unearthed at today's hearing also revealed a Foreign Office official predicted that a fatal car crash involving a diplomatic immunity claim would cause a public scandal 25 years before Mr Dunn's death.
Harry Dunn, 19, was killed when his motorbike collided with a car outside RAF Croughton
The FCDO maintains that Ann Sacoolas did have diplomatic immunity as the US-UK waiver only applied to staff at RAF Croughton, and not to their family members. Harry Dunn's parents Charlotte Charles and Tim Dunn watched today's hearing from home in Oxfordshire today
A briefing note sent to Sir Tony Baldry, then junior FCO minister, in 1995 raised concerns that ‘an accident involving the claim of immunity could make the local if not national headlines.’
Foreign Secretary Dominic Raab’s office was warned that the case could cause some ‘very unpalatable headlines’ three days after the August 2019 crash, in a briefing note copied to his private secretary.
But the Foreign Office told Harry Dunn’s family Mr Raab was only made personally aware of the case after Sacoolas fled justice on September 15th, 19 days after the teenager died.
Northamptonshire Police were also urged by the Foreign Office to delay telling his family that detectives had been prevented from interviewing Sacoolas under caution because the US insisted she maintain diplomatic immunity.
Detective Inspector Louise Hemmingway said in her statement that the Foreign Office had requested the delay while they ‘gain agreement on next steps’ after the waiver to her diplomatic immunity was refused.
Harry Dunn's mother Charlotte Charles watched High Court proceedings from home today, as the hearing was told Sacoolas 'never had any relevant immunity'
Earlier today the Foreign Office was accused of keeping police investigating the crash that killed Harry Dunn in the dark for two weeks over whether the driver had diplomatic immunity.
Mr Dunn's parents, Charlotte Charles and Tim Dunn, claim the Foreign, Commonwealth and Development Office (FCDO) wrongly decided Sacoolas had diplomatic immunity and unlawfully obstructed Northamptonshire Police's investigation into their son's death.
Ms Charles and Mr Dunn initially also took legal action against Northamptonshire Police but that claim was dropped in July, with the family's spokesman saying the force had been 'absolved of any blame'.
Ms Charles listened fromhome in Oxfordshire as she heard the UK and US agreed in 1995 that administrative and technical staff at RAF Croughton