Human rights legislation could bar police from using evidence gathered with automatic number plate recognition cameras in court, a report warned today. Chief Surveillance Commissioner Sir Andrew Leggatt urged Home Secretary John Reid to bring forward legislation swiftly to bring the hi-tech equipment in line with privacy laws. In his annual report to Prime Minister Tony Blair, Sir Andrew described how ANPR was "very effective in crime reduction" and "a prime example of intelligence-led policing". The technology, which alerts officers when a suspect number plate passes before a camera, is used by police forces across the UK to spot stolen cars and untaxed or uninsured drivers as well as vehicles believed to have been used in crime. According to the Metropolitan Police's annual report for 2005-06, ANPR teams in London supported 80 operations in the last 12 months involving gun-related crime alone, leading to 259 arrests for offences including offensive weapons, assault, burglary and immigration irregularities. The Met's mobile ANPR intercept teams are reported to have made more than 3,000 arrests over the same period. But Sir Andrew warned that use of the cameras was vulnerable to challenge in court under laws designed to regulate the state's ability to use covert surveillance against crime suspects and prevent unnecessary breaches of privacy. The Regulation of Investigatory Powers Act of 2000 (RIPA) requires police and local authorities to obtain authorisation for any operation involving intrusive surveillance. Authorisation is generally granted in relation to operations against specific suspects. But Sir Andrew said that if an ANPR camera was set up to record any of the large number of vehicles which may have been entered on police computers as being suspect - and particularly if the system was linked to Highways Agency computer records - it was "unlikely" that the operation could be authorised under the terms of RIPA. "There may well be human rights issues arising in connection with any use of private information to build up pictures of the movements of particular persons or vehicles," he warned. "In such a case, the admissibility at trial of evidence obtained in this way would probably depend on whether its admission would have an adverse effect on the fairness of the proceedings." It was the unanimous view of the seven surveillance commissioners - all of whom have held senior judicial office - that existing legislation "is not apt to deal with the fundamental problems to which the deployment of ANPR cameras give rise", said the report. "The commissioners are of the view that legislation is likely to be required to establish a satisfactory framework to allow for the latest technological advances. "I am accordingly urging upon the Home Secretary the desirability of promoting such enabling legislation as may be needed." Sir Andrew said that the omission of ANPR cameras from the Act was simply due to the fact that the development and widespread use of the technology had not been envisaged at the time it was drafted. Speed cameras operated by police do not require authorisation under RIPA because they are not hidden and drivers are alerted to their presence by signs. Sir Andrew's annual report - his last before his retirement from the post - recorded that law enforcement agencies granted some 23,628 directed surveillance authorisations in 2005-06, compared to 25,518 in the previous year. Some 4,559 "human intelligence sources" - or police informers - were recruited during the year, and 4,075 were in place at the end of March 2006, compared to 4,452 at the same point of the previous year.