During the recording it was noticed that a suspicious pattern of coughing could be heard.

Bosses say a computer system will identify rogue numbers by monitoring calls to its ten million domestic customers and noting suspicious patterns.

The security of the nation hinges on speedy information and identifying suspicious patterns of behaviour.

While there are legitimate reasons to issue refunds and cancel sales, most large retailers use automated systems that monitor till activity and highlight suspicious patterns in such transactions.

The computer program will monitor 75 million transactions a day by branch and call-centre staff in an attempt to identify suspicious patterns and nail the culprits.