"We have been working closely with the Metropolitan Police following a security breach at our Swiss Cottage branch in April 2013. 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."
ight men have been arrested by police accused of stealing £1.3m from a branch of Barclays bank in a sophisticated heist using key-logging devices installed on the premises.
The device - a keyboard, video and mouse (KVM) switch with a 3G modem attached - was installed in the branch on 5 April by a member of the gang posing as an IT engineer in order to gain access to the branch and its PCs.
The KVM was subsequently used to gather credit card and bank account information and to remotely transfer funds into other bank accounts.
Thousands of debit and credit cards, and people's personal data were seized following police raids on properties in Westminster, Newham, Camden, Brent and Essex, including what police claim is the "control room" in Marylebone, central London, from where the gang's operations were coordinated.
While £1.3m was taken from accounts as a result of the attack, Barclays claims that it was able to recover "a significant amount" of the stolen funds.
The men, aged between 24 and 47, are in custody at various police stations in London, where they are being held on suspicion of conspiracy to steal and conspiracy to defraud.
"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," detective inspector Mark Raymond of the Metropolitan Police's Central e-Crime Unit told the BBC.
In a statement, Barclays was keen to reassure customers.
"We have been working closely with the Metropolitan Police following a security breach at our Swiss Cottage branch in April 2013. We identified the fraud and acted swiftly to recover funds on the same day," it said.
The statement continued: "We can confirm that no customers suffered financial loss as a result of this action."
The attack mirrors a similar incident at a branch of Santander, also in London, just last week. In that incident, 12 men were arrested following a tip-off, enabling police to apprehend the attacker posing as an IT engineer at the targeted branch.