Watchdog reveals phone-tapping blunders

An astonishing series of blunders by the security services was revealed yesterday in a report that showed they had repeatedly tapped the wrong phones and opened the wrong letters.

M15, M16 and GCHQ listened in to unsuspecting people after mistaking their phone numbers for those of suspects. The National Criminal Intelligence Service even monitored the phone calls of one of its employees after his mobile number was mistaken for that of a "known criminal" and included on a tapping authorisation signed by officials.

A postcodes mix-up meant the security services read the mail of innocent people.

The annual report of Sir Swinton Thomas, the interception of communications commissioner, says 43 errors involving phone-tapping or intercepting post were reported to him.

The report records errors by the Home Office, by the covert listening station GCHQ, M15, M16, the National Criminal Intelligence Service and telephone service providers.

"The most common cause of error is a simple transposition of number by mistake, eg 3142 instead of 3124," said Sir Swinton.

The report showed a drop in the number of authorisations granted by the Home Secretary, from 2,080 in 2000 to 1,314 last year. But there was a 15 per cent rise in applications and many "warrants" were modified with the agreement of officials.