Britain on Friday scolded the United States for refusing to extradite a U.S. diplomat's wife who was involved in a car crash that killed a British teenager.

British prosecutors had requested the extradition of Anne Sacoolas over the crash last August in which 19-year-old Briton Harry Dunn was killed while riding his motorbike. But the State Department said on Thursday that Sacoolas had "immunity from criminal jurisdiction" and that to extradite her would set a precedent.

"If the United States were to grant the UK's extradition request, it would render the invocation of diplomatic immunity a practical nullity and would set an extraordinarily troubling precedent," the State Department said.

Anne Sacoolas
Anne Sacoolas YouTube Grab/ The Sun

Dominic Raab expressed his disappointment

British Foreign Secretary Dominic Raab called the U.S. ambassador in London to express British disappointment.

"We feel this amounts to a denial of justice, and we believe Anne Sacoolas should return to the UK," Raab said. "The UK would have acted differently if this had been a UK diplomat serving in the U.S. ...

"We are now urgently considering our options."

Dunn's family have said Sacoolas was driving on the wrong side of the road at the time of the crash, near an air force base in central England used by the U.S. military.

Sacoolas was given diplomatic immunity and left Britain shortly after the accident. Her lawyer has said that she will not return voluntarily to Britain possibly to face jail for "a terrible but unintentional accident".

British Prime Minister Boris Johnson has said Sacoolas was wrong to use diplomatic immunity to leave Britain and has urged U.S. President Donald Trump to reconsider the U.S. position.

Dunn's parents met Trump at the White House in October. Trump hoped to persuade them meet to Sacoolas, who was in the building at the same time, but they declined.