The parents of teenage motorcyclist Harry Dunn have pleaded with the head of the armed forces to set up a meeting with a US military base after claims of “three near misses” involving their staff.

Charlotte Charles and Tim Dunn wrote to Gen Sir Nick Carter on Sunday to say they “bear our American friends no ill will”, but insisted RAF Croughton in Northamptonshire could not “practice splendid isolation” on safety issues.

Their 19-year-old son was killed when his motorbike crashed into a car outside the base in August last year.

Dunn’s alleged killer, 42-year-old Anne Sacoolas – the wife of a US intelligence official based at RAF Croughton, claimed diplomatic immunity following the crash and was able to return to her home country.

Since the collision, Northamptonshire police said it investigated two further incidents of Americans allegedly driving on the wrong side of the road.

On Wednesday, RAF Croughton said it was co-operating with police over a third incident after claims another member of staff smashed into a fence after driving on the wrong side of the road.

Dunn’s family have said despite the force’s chief constable offering driver training at the base, “there is so much more ... that needs to be done”.

In the letter addressed to Gen Carter, Mrs Charles and Mr Dunn said: “We bear our American friends no ill will and simply wish for them to sit down with our advisers to take things forward.

“The base commander has met with the chief constable who has offered driver training, but there is so much more than that that needs to be done.

“We are aware of the legal arrangements between the MoD and the USAF and that they retain jurisdiction over their own personnel.

“However, we also know that the MoD should be overseeing the work that they do.”

The letter continued: “They cannot practice splendid isolation on this and other safety issues.

“Confidence and trust has been severely eroded since Harry died and relations between the base and the community are at an all time low.

“We dare say they are feeling terrible as well. But we have lost our precious son.

“Let his loss be the last. Safety must come first, always.

“Could we ask you please to use your best endeavours to persuade your American colleagues to meet us so that we can rebuild the relationship and work together on this most important of initiatives.”