Government snooping of electronic communications has come under fire in the Information Commission's annual report.
Information Commissioner Elizabeth France said that the Government's use of the terrorist attacks in the US as justification for increased monitoring of people's email and internet usage is of "continuing concern".
Just last month the Home Secretary was forced to rethink plans to allow a wide range of non-law enforcement public bodies access to monitoring data held by internet service providers (ISPs) under the Regulation of Investigatory Powers Act.
"These include not just the prevention and detection of general criminality, but matters relating to public health and tax collection," said France.
"The potential for access for these much wider purposes to information that is, on the face of it, retained only for safeguarding national security, causes us real concern."
France warned that any legislation that forces ISPs to retain billing and traffic data for law enforcement purposes must be used for just that.
"We must be careful to analyse properly the case made for retention whether, as it once was, based primarily on addressing the use of the internet by paedophiles or, as is now the case, based on the use of the internet by terrorists," she said.
Elsewhere, the report reveals that complaints to the Information Commission about the misuse of personal data are up almost 50 per cent, from 8,875 last year to 12,479 this year.
Data protection awareness by data controllers is also up, however, from 78.7 to 83 per cent. The number of offences that led to prosecution rose from 23 to 66, resulting in 33 convictions.
The Commission is also in the first year of a two-year £5m programme to modernise its IT systems, which will include a new IT infrastructure, connection to the Government's secure intranet BS7799 security accreditation, and an electronic notification system for data controllers.
France will be leaving her post as Information Commissioner in October after eight years to become the Telecoms Ombudsman.
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