The identity of six informants has been revealed in the past 12 months

The government's supposedly anonymous money laundering reporting system has breached informant confidentiality six times in the past 12 months.

Of the 220,000 reports to the Suspicious Activity Report (SAR) system in 2007, six identities were revealed, two of them from HM Revenue and Customs, according to the committee that oversees the multi-agency scheme.

The system was established to co-ordinate reports of illegal financial dealings, particularly to do with the proceeds of crime, to the Serious Organised Crime Agency.

"Breaches are a major concern – I am encouraged that Soca has imposed serious conditions on end-users to try and prevent this," said Karen Silcock, who sits on the SARs Regime Committee.

"But there can never be a 100 per cent guarantee that the source of a SAR will not be released."

The proportion of breaches is small and the situation is improving, according to the committee.

"While we accept that any breach of confidentiality is unacceptable, the low numbers indicated suggest that this problem is not as widespread as it once was, " says the annual report (PDF) published today.

The SARs database can be accessed by 75 different agencies including police, central government departments and the industry watchdog, the Financial Services Agency.