A group of alleged cyber plotters, including an estate agent from Gospel Oak, are accused of stealing £1.3million from a bank branch in Swiss Cottage by taking control of its computer system.

Ham & High: An image of a 'KVM' device, which was used in the alleged theft. Picture: Metropolitan Police ServiceAn image of a 'KVM' device, which was used in the alleged theft. Picture: Metropolitan Police Service (Image: Archant)

Four men have been charged in connection with the theft at Barclays bank in Finchley Road in April after police arrested eight people during an operation last Thursday.

It is believed somebody posing as an engineer at Barclays branch planted a device called a “keyboard video mouse” that allowed the alleged thieves to access accounts.

Police believe the gang that targeted Barclays had a “control room” in Seymour Place, Marylebone, and one of the men arrested was described by police as the “Mr Big of UK cyber crime”.

Officers carried out a secret intelligence operation to target the network and raided addresses in Camden, Westminster, Brent, Newham, and Essex.

Police seized cash, jewellery, drugs, thousands of credit cards and personal data and they discovered a control room where they believe the gang allegedly masterminded cyber crime on a scale not seen before in Britain.

Det Supt Terry Wilson said: “We’ve actually been quite astounded by what we’ve come across, which effectively is a cyber crime control room in Seymour Street in Marylebone.”

Romanian national Darius Bolder, 34, of Ebury Bridge Road, Chelsea, and Tony Colston-Hayter, 47, of Ilminster in Somerset, are alleged to have set up the sophisticated system to siphon off cash and are charged with conspiracy to steal from Barclays.

Estate agent Michael Harper, 26, of Kiln Place, Gospel Oak, and Lewis James Murphy, 29, of Ebury Bridge Road, Chelsea, were charged with credit card fraud linked to up-market retailer Selfridges.

None of the men entered a plea on the charges when they appeared at Westminster Magistrates Court on Friday and they were remanded in custody to appear at Southwark Crown Court next month.

A further four men who were arrested last Thursday have been released on bail.

Det Insp Mark Raymond said: “Those responsible for this offence are significant players within a sophisticated and determined organised criminal network, who used considerable technical abilities and traditional criminal know-how to infiltrate and exploit secure banking systems.”

Alex Grant, Barclays’ managing director of fraud prevention, said the bank had “acted swiftly”.

He said: “We identified the fraud and acted swiftly to recover funds on the same day. We can confirm that no customers suffered financial loss as a result of this action.”