One of the men trying to launder the stolen money, Ansmana Kamara, 31, was jailed for 3½ years on Monday at Southwark Crown Court after pleading guilty to a variety of fraud charges. The ODA, which is in charge of more than £7 billion of construction in relation to the Olympics, had been contacted by the fraudsters last year. They claimed to work for a company called Skanska, one of the contractors on Olympic Park.

They told the ODA the company had a new bank account and wanted future banking payments changed. The ODA obliged, transferring £2.3 million into a bogus law firm account controlled by Kamara. However, when Kamara tried to transfer £2 million to Nigeria, suspicious staff at the money transfer bureau notified the police.

The ODA is understood to have recovered nearly all of the money. The court was told Kamara, originally from Sierra Leone, was the son of the national chief of police in that country. Kamara fled to Britain in 2001 after his father was hanged following a military coup. A spokesman for the ODA said: “Early identification greatly reduced the potential impact of this fraud with almost all of the monies recouped shortly after it occurred last summer.”