A clampdown was launched shortly after Libyan officials used diplomatic immunity to thwart an investigation into the 1984 murder of police constable Yvonne Fletcher, who was killed by a shot from the Libyan People's Bureau in London.
Until then diplomats openly abused the system, under which they are immune from prosecution by British law, notching up 22,337 unpaid parking tickets in 1986. That number fell to 1,586 in 1995. Among the worst parking culprits were the United Arab Emirates, Qatar, Saudi Arabia, Angola, and Nigeria.
Last year there were 34 serious offences, which included 18 drinking and driving cases and a number of thefts and shoplifting incidents.
There are about 2,500 people with diplomatic status in Britain and an additional 7,000 dependents, all of whom under the Diplomatic Privileges Act 1996 are exempt from British law.
But the Foreign Office has been placing increasing pressure on governments and ambassadors for their representatives to obey our laws and waive immunity in cases that are considered serious.
A Foreign Office spokesman said: "After the Yvonne Fletcher case we looked closely at the issue - we have taken a much tougher approach now."
Despite the crackdown, there has still be a series of high-profile cases in which diplomats have apparently used their status to escape justice.
When PC Fletcher was shot in 1984 outside the Libyan embassy, her killer was believed to be a diplomat inside. But he was never brought to justice.
James Ingley, an American lay preacher, was accused of a sex attack on a six-year-old girl in his care in 1987. His wife worked at the US Embassy in London and the charges were dropped.
In 1986 Indian envoy Babu Lal Gupta, who was accused of plotting to smuggle pounds 320,000 worth of heroin into Britain, also escaped prosecution.
Cuba's ambassador Dr Oscar Fernandez-Mell was expelled in 1989 after one of his officials fired live bullets in a crowded London street, narrowly missing a bus.
And only last month Iris Ramirez-Paget, for five years the first secretary at the Honduras Embassy in London, fled Britain after being accused of fraudulently obtaining pounds 36,000 in housing benefit and thousands of pounds in income support.
But the number of offences has been dropping and evidence of the tougher line was provided last July when a Zimbabwean diplomat who twice claimed immunity after driving under the influence of alcohol in London was recalled. The Zimbabwe Foreign Affairs Ministry summoned back Charles Mayengehama, 33, the First Secretary at its High Commission in the Strand.