The mother of teenage motorcyclist Harry Dunn has said she has “a lot of faith in the CPS that justice will be done” after a court hearing for her son’s alleged killer was postponed.

Charlotte Charles told the PA news agency her family “just have to bear with them for a while longer” as she marked what would have been Mr Dunn’s 22nd birthday on Tuesday.

Foreign Secretary Liz Truss said the Foreign Office continues to stress “the importance of the virtual trial taking place urgently” to its US counterparts.

The Crown Prosecution Service (CPS) previously said in a statement that the case of 44-year-old US citizen Anne Sacoolas would be heard at Westminster Magistrates’ Court in January, before the hearing was vacated.

Sacoolas is accused of causing 19-year-old Mr Dunn’s death by dangerous driving following a fatal crash outside US military base RAF Croughton in Northamptonshire on August 27 2019.

The suspect had diplomatic immunity asserted on her behalf by the US government following the collision, and was able to leave the UK 19 days after the incident.

The CPS said the hearing was vacated to “enable ongoing discussions” and a new date has not yet been fixed.

In a tweet issued on Tuesday, the Foreign Secretary said: “Harry Dunn’s family are in my thoughts and have my full support.

“I know how painful the anniversary of Harry’s birthday will be without justice yet being fulfilled.

“We continue to stress to our counterparts in the USA the importance of the virtual trial taking place urgently.”

Speaking to PA on what would have been Mr Dunn and his twin brother’s birthday, Mrs Charles said: “Today’s another tough day for myself and my family.

“It’s a bittersweet day – it’s Harry and Niall’s 22nd birthday – so birthday number three for all of us without Harry.

“We’re at home, continuing to just fight and keep this campaign going.”

She continued: “It’s going to be a quiet day – one for reflection.

“We’re going to keep ourselves very much to ourselves like we have been recently for very good reason.”

Addressing the postponed court date, Mrs Charles said: “Although justice hasn’t been done yet, I’ve got a lot of faith and a lot of belief in the CPS that justice will be done.

“We’ve just got to bear with them for a while longer.”

Mrs Charles told PA the support she was receiving from Government officials and from people across the UK was giving her the strength to carry on her campaign for justice.

She said: “Thank you to the officials at the Foreign Office, thank you to our many, many supporters in the UK and indeed the USA and around the world.

“Without your continued love and support, I wouldn’t be sat here finding the strength to carry on fighting for my boy.

“The determination is still as strong as it ever has been and you keep me going.

“So thank you. Stay with us.”