With diplomatic immunity playing a key role in the investigation into the death of 19-year-old Harry Dunn in a crash outside an RAF base in Northamptonshire, what is it and when has it been used before?

• What is diplomatic immunity?

Diplomatic immunity is a legal exemption from certain laws granted to diplomats by the state in which they are working.

It ensures they will not be liable to prosecution under the host country’s laws.

It is governed by an international treaty called the Vienna Convention on Diplomatic Relations (VCDR) and UK legislation called the Diplomatic Privileges Act (DPA).

• What would have to happen in order for someone who has been granted diplomatic immunity to face prosecution?

The only way for somebody who has been granted diplomatic immunity to face prosecution would be for their country of employment to waive their immunity.

In the case of Harry Dunn, the US would have to waive the suspect’s immunity if they were to face prosecution in the UK.

Harry Dunn with his mother Credit: Charlotte Charles/PA

• Can diplomatic immunity be provided to anyone who isn’t a diplomat?

Diplomatic immunity can also be provided to a diplomat’s family members and spouses.

In this case, diplomatic immunity has been given to the wife of a US diplomat.

• What punishment, if any, can people with diplomatic immunity face?

They cannot face prosecution, but they can be expelled from the country they are working in.

• If you have diplomatic immunity, are you allowed to break whatever rules you like?

Under the terms of the VDCR treaty, diplomats are asked to obey the rules of the host country.

If they do not, they face expulsion from the country they are working in.

• When has diplomatic immunity been granted before?

One of the most famous cases involving diplomatic immunity was the death of Metropolitan Police officer Yvonne Fletcher, who was shot dead from the window of the Libyan embassy in 1984.

After an 11-day siege at the embassy, all those inside made their way out and were granted diplomatic immunity.

The incident severed diplomatic relations between the UK and Libya.

In December last year, the Foreign Office said a diplomat had been expelled from the UK after allegations of two rapes and one attempted rape from 2017.

The diplomat involved was thrown out of the country after their home country rejected the request to waive their immunity.

Other allegations relating to 2017 included one report of sexual assault involving an individual representing Algeria, one of blackmail (Egypt), and one possession of a firearm with intent to injure (Cambodia).

• Are there examples of when immunity has been waived?

In 2003, Colombian diplomat Jairo Soto-Mendoza was forced to stand trial in the UK accused of killing a man who mugged his son after his home country waived his immunity.

It took until four months after the incident for Mr Mendoza’s immunity to be waived.

He was found not guilty of murder and manslaughter.

In 1997, Georgian diplomat Gueorgui Makharadze had his immunity waived by his government after he caused a five-car pile-up in Washington DC, resulting in the death of a teenage girl.

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