Ten men and two women - aged between 21 and 33 years old - were arrested in the early morning raids across London this morning on allegations including conspiracy to steal and conspiracy to money launder.
They have been taken to three separate police stations in the capital and are being interviewed by police. Police did not yet know exactly how much money had been recovered from two of the premises searched.
Scotland Yard said officers would continue to carry out searches at a number of residential and business addresses across London for several more hours. The arrests took place at addresses in Norwood Green, Southwall, Northolt, Isleworth and Hounslow.
The robbery took place on March 19, when thieves apparently hijacked a Securicor van containing two silver cashboxes that had just been unloaded from a South African airlines plane.
The driver of the van told police that he was sitting in the driver's seat when the two suspects approached him and instructed him to drive from the airport to Church Road, Cranford, where the cashboxes were transferred into another vehicle, police reported today. Initial reports suggested the 21-year-old driver, who was believed to be among those arrested today, had been held at knifepoint. He was unhurt and alerted police to the incident.
Detective Chief Superintendent John Coles, of the Metropolitan police, said: "Today's arrests are the culmination of a two month pro-active operation by the Met's Flying Squad. This robbery was one of the biggest to take place in recent years."
Mr Coles said the investigation into the robbery will continue, and he urged anyone with information to contact the police or Crimestoppers.
The robbery in March came just five weeks after a similar incident at Heathrow, in which thieves hijacked a security van near terminal 4 and made off with £4.6m in foreign currency.
