The Foreign Office has waived diplomatic immunity for 13 British citizens accused of crimes in the United States since 1999, The Mail on Sunday has learned.

Britain has not refused a single request from Washington to prosecute a serving diplomat in that time. In contrast, it is understood the US has not reciprocated over its officials during the same period.

The news will reignite the row over the death of Harry Dunn, the teenage motorcyclist hit by a car driven by American Anne Sacoolas close to the RAF base where her husband worked.

She was later charged with causing death by dangerous driving but by that time she had already fled the country. The US has refused to extradite her, claiming that, as the wife of a serving diplomat, she has immunity.

Harry Dunn died after being hit by a car driven by American Anne Sacoolas close to the RAF base where her husband worked. She has diplomatic immunity so went home to the USA

The Foreign Office insists it was powerless to stop Mrs Sacoolas leaving, and even suggested in a text to the US Embassy after the accident that she fly home 'on the next flight'.

Officials later made efforts to get Mrs Sacoolas's immunity waived and this newspaper revealed that she was a former CIA spy.

Mr Dunn's family is taking the Government to the High Court and it is understood the Foreign Office intends to use its 'surprise and disappointment' at the US refusal to waive immunity as part of its defence.

Under the 1961 Vienna Convention, diplomats and their families cannot be arrested or prosecuted.

However, there are side treaties between the US and UK. Mrs Sacoolas's husband Jonathan worked at RAF Croughton in Northamptonshire, and under a 1995 exchange of diplomatic notes he was liable for any crime committed outside of his direct work.

But as there was no explicit mention of spouses, Mrs Sacoolas is immune from prosecution. Last night, the Dunn family spokesman Radd Seiger said news that Britain had waived immunity for its own diplomats 'lays bare the extent to which there is, in fact, no special relationship between the US and UK'.

Pictured: British teenager, Harry Dunn, who was killed after being hit by a car driven by Anne Sacoolas

Mr Seiger called for Mr Dunn's case 'to be the last of its kind', adding: 'Never again will we the people allow the US government to treat us with utter disdain, those in power in Whitehall clearly being unable to stand up to their bullying and oppression.'

Tory MP Tom Tugendhat, chairman of the Commons Foreign Affairs Committee, said last night: 'Any score that ends up 13-0 makes it look like the ref is biased. 'We need to make sure our friends in the US are playing by the same rules. If they're not, nor should we.'