Motorists parking illegally on some of the busiest roads in central London could now be caught using CCTV cameras.
About 20 cameras are being used to find drivers who break the law
About 20 cameras have been set up in the West End and elsewhere, to film cars parked on double yellow lines or causing an obstruction.
Drivers will then be sent a fine in the post - it is hoped firm evidence provided by the cameras will mean less tickets are challenged.
But the AA said cameras were "too blunt an instrument" to be used alone.
Spokesman Paul Watters said: "An attendant on the street will stop many chancers from parking illegally whereas a camera clicks away remotely and it won't spot the blue badge or note on the windscreen about the car being broken down."
He said areas where the cameras were used would have to be clearly signposted.
Westminster City Council has said traffic wardens would still be used in the area. It is hoped that cameras will also spot attacks on the wardens, for use in prosecutions.
Councillor Danny Chalkley said: "Our pilot scheme proved that CCTV is reliable and cost-effective. CCTV cameras mean more tickets will be right first time.
"Westminster remains the leading authority in parking enforcement that continues to improve and be firm, fair and excellent."
The cameras follow a successful trial scheme earlier this year.
For the first three weeks the council will run an awareness campaign and drivers will receive a warning, rather than a fine through the post.
In 2005/2006 Westminster City Council received £31.1m from 715,000 parking tickets.