A DOWNING STREET staff member labelled Harry Dunn’s family spokesman a “bad guy” in an internal email after the latter voiced concerns of a potential cover-up over the teenager’s death.

Mr Dunn’s mother Charlotte Charles has demanded an urgent meeting with PM Boris Johnson and a personal apology to the spokesman Radd Seiger.

The email was in response Mr Seiger’s statement on Twitter after a meeting with United States President Donald Trump in October, in which he wrote that the family were intent on exposing “misconduct … on both sides of the Atlantic.”

Commenting on the email from the unnamed staffer, a Downing Street spokeswoman said: “We apologise for the content of this email, which was inappropriate.”

Mr Dunn was 19 when he died in a crash involving his motorbike and a car outside RAF Croughton in Northamptonshire last year.

The US asserted diplomatic immunity for his alleged killer Anne Sacoolas, the wife of a CIA officer working in Britain. She returned to the US almost three weeks after the crash.

She was charged with causing death by dangerous driving in December, but the Home Office’s extradition request was rejected by the US State Department in January.