The wife of a US intelligence officer involved in a fatal collision that killed British teenager Harry Dunn could be handed an Interpol red notice, meaning she risks arrest if she ever leaves the US.

Anne Sacoolas, 42, was wrongly granted diplomatic immunity after the crash in Northamptonshire on August 27 when she hit 19-year-old Mr Dunn’s motorcycle.

It is understood Mrs Sacoolas was driving on the wrong side of the road.

She was “spirited out” of the UK on a military aircraft three weeks after the incident and Mr Dunn’s family have been told by the US security adviser that she will not be returning to face justice.

Robert O’Brien instead tried to orchestrate a meeting between the teenager’s parents and Mrs Sacoolas at the White House, to be followed by a photo opportunity where he hoped the parties would embrace.

The family’s lawyer Mark Stephens branded Mr O’Brien a “nincompoop in a hurry” for the failed stunt.

He added: “Having ice in your veins is a very good characteristic for being a spy but thinking you can treat human beings in that way, you would have to be a nincompoop.

“He’s piled additional grief and hurt on the Dunn family that was entirely unnecessary – he started it by causing her to be a fugitive from justice, spiriting her out of the country on US Air Force transport without telling the Northamptonshire Police.”

Robert O’Brien
National security adviser Robert O’Brien (Evan Vucci/AP)

The family declined to meet Mrs Sacoolas, although they added that Donald Trump said “let’s try and come at this another way” and were hopeful he would take steps to move the situation forward.

Northamptonshire Police said they would soon submit a case file on the crash to the Crown Prosecution Service for a charging decision.

If Mrs Sacoolas is charged with causing death by careless driving, or a more serious charge of causing death by dangerous driving, the force can issue an extradition request or a red notice by Interpol.

The family also have the option of bringing a civil case against Mrs Sacoolas.

Charlotte Charles, her husband Bruce Charles and Tim Dunn arrive in Washington
Harry Dunn’s mother Charlotte Charles, her husband Bruce Charles and the teenager’s father Tim Dunn arrive in Washington (Manuel Balce Ceneta/AP)

“It is often not understood that diplomatic immunity only applies in the host country, so the UK, not in the home country – it evaporates the moment you set foot on US soil,” Mr Stephens said.

“It wouldn’t be about money, it would be about trying to ensure she gives an account and has accountability.”

Mrs Sacoolas was wrongfully given immunity because her husband is an intelligence official and was not in a recognised diplomatic role such as military attache or trade secretary.

Even diplomats are only entitled to immunity once they have taken their credentials to be registered at the Foreign Office.

Diplomats who commit an offence between being appointed to a role and registering at the Foreign Office may still be prosecuted.

The scene of the collision outside RAF Croughton
The scene of the collision outside RAF Croughton (Steve Parsons/PA)

Mr Stephens said that by making Mrs Sacoolas a “fugitive” it was obvious US officials knew she was not entitled to immunity, as the purpose of the law is to allow diplomats to continue to work in their host country.

“It’s almost unique, in fact I think it is unique, that someone who is claiming diplomatic immunity has fled from justice and fled from scrutiny of their diplomatic status.”

He said he understood the US had not wanted to blow her husband’s cover, but had created an interest in the case which would otherwise have only attracted a community sentence and little media attention.

Northamptonshire Police said: “We we will do everything on our side to ensure a full and thorough investigation takes place in order to get the justice Harry and his family deserve.

“Furthermore, we are working very closely with the Crown Prosecution Service with whom we visited the collision site earlier today. It’s our expectation that we will be able to submit a case file very shortly to the CPS.

“The police investigation is still under way and, if appropriate, a file of evidence will be submitted when the investigation is completed.”

Mr Stephens said the force had the option of making an extradition request or placing an Interpol red notice on Mrs Sacoolas.

“So if she goes to Canada or Mexico or some other jurisdiction she’ll be arrested at the border and returned to the UK,” he said.