Harry Dunn's parents have called for the return of a US diplomat's wife who was involved in the traffic collision that killed their son.

Harry's mother, Charlotte Charles, told the BBC the family had been left "utterly devastated" by the death of the teenager, from Charlton, Banbury, on 27 August.

His father, Tim Dunn, said they needed to get the truth.

The diplomat's wife, who is a suspect in the case, left the UK despite telling police she did not plan to.

She is lawfully entitled to claim diplomatic immunity, according to Chief Constable Nick Adderly.

He added that both he and the crime commissioner had written to the US Embassy in London urging that the diplomatic immunity waiver be applied "in order to allow the justice process to take place".