The mother of Harry Dunn has appealed to the government to make her son “top priority” during the US Secretary of State visit.
Charlotte Charles asked Boris Johnson, Foreign Secretary Dominic Raab and Mike Pompeo to “please, please, discuss Harry” at the visit on Monday.
Mr Dunn, 19, died after a crash outside RAF Croughton, following which the suspect – Anne Sacoolas – fled the UK.
Mr Raab said there are “no measures” to force the United States to comply.
In a video message, Mrs Charles, said: “Mr Raab, Mr Pompeo, Mr Johnson, when you get together next week with all of your families fully intact whilst mine is in complete tatters and my family has been ripped apart, can you please, please discuss Harry?
“We’ve been assured he’s high on your list of priorities to discuss amongst all of the other important global issues that you have surrounding you but please, please make him top priority.”
Motorcyclist Mr Dunn died in a crash with a car at the Northamptonshire US military base on 27 August.
She said the past 11 months have been “horrific” and she would not wish what she has gone through “on your worst enemy”.
“We’ve got his anniversary coming up which is going to be beyond painful for us”, she said.
“It’s just about doing the right thing. It always has been, it always will be.”
Mrs Sacoolas – the wife of a US intelligence official based at RAF Croughton – sparked an international row when she claimed diplomatic immunity after the crash.
The 42-year-old was charged with causing death by dangerous driving in December.
A Home Office extradition request was refused by US secretary of state Mike Pompeo in January.
A state department’s spokeswoman said that decision was final.
“We’ve always agreed immunity does need to be in place for certain circumstances. This isn’t one of them”, Mr Dunn’s mother said.
“Bring Anne Sacoolas back to the UK, face the justice system.”
“My concern is to make sure justice is served and to make sure Harry’s life is actually thought of and considered”, she added.
Mr Raab told Sky News, “there’s a denial of justice here”.
“There’s no measures that we could I think credibly, realistically take which is somehow going to force the US or indeed Anne Sacoolas to comply with this [the extradition].
“I want to be realistic because I don’t want to raise expectations which are then going to be dashed.”
He said it has been “raised” in Washington, with the prime minister and President Trump.
“We will continue to make clear we’re on the side of the family here, we think that she should return, she must return home, so that justice can be done.”