The family of the Northamptonshire 19-year-old are demanding a meeting with prime minister Boris Johnson after US secretary of state Mike Pompeo informed the government last night that the US was turning down the extradition request.
The teenager died when his motorbike crashed into a car outside RAF Croughton in August last year.
Intelligence officer’s wife Ms Sacoolas, 42, was charged with causing death by dangerous driving but claimed diplomatic immunity following the crash and was able to return to her home country, sparking an international controversy.
The incident sparked concern about driving incidents in the area, with reports of personnel from the base driving on the wrong side of the road.
In a statement, Mr Raab said: “I called the US ambassador earlier to express the government’s disappointment about this decision.
“We feel this amounts to a denial of justice, and we believe Anne Sacoolas should return to the UK. We are now urgently considering our options.
“I also explained that the UK would have acted differently if this had been a UK diplomat serving in the US.
“I emphasised that work to improve road safety on and around the Croughton base must continue, and the need to resolve the issue whereby family members at RAF Croughton are immune from criminal prosecution.”
Family spokesperson Radd Seiger said Harry’s parents Tim Dunn and Charlotte Charles were informed of the rejection of the extradition request in a phone call from their constituency MP Andrea Leadsom late on Thursday.
Ms Leadsom is due to meet the US ambassador Woody Johnson in London on Friday to discuss the case.
Mr Seiger said the US decision marked “one of the darkest days” of the UK/US special relationship.
He told BBC Radio 4’s Today: “That’s the first time in history that the United States has turned down an extradition request. It’s one of the darkest days in the history of this special relationship.
“Boris Johnson wanted to be prime minister, he is now being tested severely. I expect him today to rise to that challenge and come and meet with me and the family and tell us what he’s going to do about it.”
A Downing Street spokesperson said he was not aware of any plans for a meeting between Mr Johnson and the family.
“We will carefully consider what future action can be taken,” said the spokesperson. “The Crown Prosecution Service is currently considering the legal position.”
Asked whether the US response would undermine transatlantic relations, he replied: “We continue to have a close and longstanding relationship and that remains the case.”
Mr Seiger said the family remained confident that Ms Sacoolas would one day face the UK courts.
“We know for sure that she will be coming back one day, there is no other way forward,” he said.
“The reality is that this administration, which we say is behaving lawlessly and taking a wrecking ball to one of the greatest alliances in the world, they won’t be around forever, whereas that extradition request will be.
“We will simply plot and plan for a reasonable administration to come in one day and to reverse this decision.”