Several months after the country's surveillance chief questioned whether it is legal to scan car number plates, the Home Office has launched an official review of the technology.

In July, Computeractive reported that the Government's chief surveillance commissioner, Sir Andrew Leggatt, had said it might not be legal to use automatic number plate recognition cameras to provide evidence in court.

The cameras, in place around the country, read the number plates of all passing cars, using computers to read the numbers and compare them with a database of known suspect vehicles.

According to Sir Andrew, the technology could be in breach of the Regulation of Investigatory Powers Act.

The Home Office has now said that it is investigating the matter, to find out whether the law needs to be changed.