It comes as new figures given to MPs showed that 15 serious and significant offences, including sexual assault and drunk-driving, were allegedly committed by diplomats or those entitled to diplomatic immunity between 2019-2022.
The new details came in two written ministerial statements published by junior foreign minister David Rutley.
The figures for alleged offences include the case of US citizen Anne Sacoolas, who hit 19-year-old Harry Dunn with her car outside a military base in Northamptonshire in 2019.
She had diplomatic immunity asserted on her behalf and was able to return to the US after Harry died, but was later convicted of causing his death in a UK court.
One diplomat or dependent from Saudi Arabia faced a historical allegation of modern slavery in 2019, while one from the US and one from Iraq faced allegations of sexual assault.
A spokesperson for the US Embassy said the mission was “aware” of Mr Rutley’s statement, but had “no comment on the specifics of this case”.
They declined to say whether the individual involved was still working at the embassy, had been withdrawn from the UK or had their diplomatic immunity waived.
Among other alleged offences were fraud by abuse of position, cruelty to a child and driving under the influence of alcohol.
Mr Rutley also said that the congestion charge debt owed by foreign embassies in London continues to grow, now totalling more than £145 million.
Since the introduction of London’s congestion charge in 2003, diplomats have claimed that it is a tax – making them exempt from paying it.
“We consider that there are no legal grounds to exempt diplomatic missions and international organisations from the London congestion charge, which is comparable to a parking fee or toll charge they are required to pay,” Mr Rutley said.
As of December 2022 the US embassy owes the largest debt, more than £14 million.
It is followed by the Japanese embassy, which has racked up more than £10 million in unpaid charges.
The Office for the High Commissioner for India owes £8.5 million, while the Chinese embassy owes nearly £8 million.
The Russian embassy owes just under £6 million.