The base is used by the US military and Sacoolas was given diplomatic immunity after the incident. She and her husband left Britain shortly afterwards.

The Crown Prosecution Service charged Sacoolas two years ago with causing death by dangerous driving. US officials rejected an extradition request submitted from the Home Office in January last year and they have described their refusal to extradite her as “final” on a number of occasions.

Radd Seiger, spokesman for Harry Dunn’s family, said: “We have full faith in the Crown Prosecution Service and will wait to hear from them with further developments, hopefully in the near future.

“Harry’s family were obviously looking forward to the hearing on Tuesday so they hope an agreement will be reached sooner rather than later.

“It is vitally important for their mental health that justice and closure is achieved soon.”

The CPS added: “Mrs Sacoolas has a right to a fair trial. It is extremely important there should be no reporting, commentary or sharing of information online which could in any way prejudice any proceedings.”