A gang of robbers who carried out Britain's biggest heist gained the trust of the manager of a cash depot and that of his wife by posing as policemen with uniforms bought on eBay before taking them hostage at gunpoint, a court heard today.

Two of the gang, who cannot be identified for legal reasons, were cage fighters who fled to Morocco after the raid at the Securitas depot in Tonbridge, Kent in February last year, where £53 million was stolen, the Old Bailey heard.

Detailed planning, possibly going back seven months before the robbery, was involved in the raid, including getting latex masks made to disguise the men posing as police officers and the buying of sophisticated surveillance equipment, including a miniature camera in a pair of jeans used to covertly video the inside of the depot, it was said.

The two fighters, who are facing extradition proceedings, were "at the heart of the conspiracy" the jury was told.

Sir John Nutting, QC, for the prosecution, said:"They were cage fighters by occupation. This activity involves two men being put in a cage and fighting until one of them submits.

"There are virtually no rules, Queensberry or otherwise. They fought on the same team."

In the months before the heist the pair were in constant contact with the alleged robbers currently on trial, it was said.

Sir John told the court that a computer belonging to a friend of one of the fighters was used to buy police clothing.

The court has heard that Colin Dixon, the manager of the depot, was pulled over on his way home by members of the gang posing as policemen before being handcuffed. His wife and young child, who were at their home in Herne Bay, Kent, were also kidnapped by men posing as officers who tricked them into getting into their car by telling them Mr Dixon had been involved in a car accident.

Sir John said: "A computer belonging to a friend (of one of the fighters) was used to purchase via eBay two Kent Police cap badges, a police pullover and a police Gore-Tex fluorescent jacket.

"Such a police pullover was worn by one of the kidnappers of Colin Dixon; such a Gore-Tex fluorescent jacket was thrown over Mrs Dixon during the journey from Herne Bay to Elderden Farm and a similar sort of jacket is worn by the robber who was dressed as apoliceman at the depot."

The court heard that mobile telephone records, which show where telephones were used and when, provide "a valuable tool in proof of involvement in the conspiracies of the defendants".

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