A Metropolitan Police detective carried out 16 thefts totalling around £80,000 at Heathrow airport between 2010 and 2015. DS Michael Harrington snatched money confiscated from passengers travelling out of the airport pending further investigations.

The cash should have been recorded and banked then returned to the owner if – following enquiries – there was no evidence it had been obtained by criminal means. But instead, Harrington, 46, kept it for himself.

In 2015, after a complaint by a member of the public that their funds had not been returned, an investigation was opened by the Met's professional standards unit (DPS).

Searches of his home uncovered items including empty cash bags and various police documents – although none of the cash was recovered.

He was arrested on 28 July 2015 and suspended from his role as a financial investigator based within the Specialist Crime and Operations.

He was part of a Criminal Finance Team that regularly seized large amounts of cash from people travelling out of the country.

Detective Sergeant Stuart Hart, from the DPS, said: "DS Harrington clearly took advantage of his position to steal a large quantity of cash that had been seized at Heathrow.

"He remains suspended and once all criminal matters are complete, misconduct proceedings will take place."

Brexit speech: Immigration
The money belonged to passengers flying out of Heathrow Neil Hall/Reuters

Harrington pleaded guilty to the offences at Southwark Crown Court on 17 October and is expected to be sentenced on 28 November. He is currently suspended from his role as a financial investigator based within the Specialist and Economic Crime Command.

He was charged on 6 April 2016 with 11 counts of theft, with another five later added to the indictment. He denied the charges at a pre-trial hearing earlier this month. His lawyer claimed the Economic Crime Unit's system "had broken down".

Edward Henry, defending, added: "People used each other's passwords, people had access to each other's cases and the integrity of the whole department was in question. When I say integrity I mean of the system."

But the disgraced DS Harrington confessed to his crime on 17 October. He will be sentenced on 28 November. To this day, none of the cash has been recovered.