Riot ringleaders are being hunted down by government spies through their phone and internet communications.

Experts at the UK Government Communications Head and Scotland Yard are tracing the exchanges between hundreds of criminals suspected of masterminding some of the worst looting.

However, the investigations are being impeded by technology on BlackBerry smartphones, which allows the rioters to send encrypted instant messages to avoid detection.

The instant messages sent via BlackBerry Messenger, known as BBM, to private networks of one or more people, are virtually untraceable.

Unlike social networks such as Facebook and Twitter, messages sent through BBM cannot be traced back to the sender.

They are also encrypted, adding to the handset’s popularity among security-conscious business chiefs and criminals alike.

The spooks from the GCHQ listening station in Cheltenham were brought in after senior officials designated bringing rioters to justice a “national priority”.

Home Office sources said “several hundred” ringleaders had already been identified by police intelligence staff.

“Many of these people are part of organised criminal gangs,” said an official. “We know who they are and we can see who else they are talking to. We are using all the resources at our disposal. This is a national priority.”

GCHQ employs some of the world’s most skilled experts in intercepting and recovering electronic communications.

Police technical experts also possess the skills to recover incriminating information from mobile phones.

This could include a record of their messages as well as photographs and internet searches. It is also possible undercover agents may have been able to infiltrate message networks.

Research in Motion, the firm that makes the BlackBerry, said it would “engage with the authorities”. The statement brought threats from hackers against the company.

Deputy Assistant Commissioner Stephen Kavanagh, of the Met, said: “A lot of people who are seeing these BlackBerry messages are forwarding them to the police.”