Drivers will be fined £120 for straying into cycle lanes under plans to give local authorities powers to install yet another set of roadside enforcement cameras.

Even minor infringements, such as moving briefly into a cycle lane to pass a vehicle turning right, will result in a fixed penalty. Drivers will not know that they have been caught until the penalty notice arrives in the post a few days later.

The powers are initially being proposed for use by authorities in London but would be introduced later across the rest of the country.

The cameras would also monitor cycle boxes at traffic lights, known as “advanced stop lines”.

Transport for London (TfL) believes that issuing thousands of penalties will make cycling safer by sending a strong message to drivers that they cannot ignore the white bicycle symbols painted on the road.

Police can already impose a £30 fixed penalty for driving in cycle lanes but only three were issued in London in the year to the end of June. A senior traffic policeman told The Times that it was very low on the list of priorities for officers and that they rarely even bothered to issue a verbal warning.

TfL is proposing that the offences be decriminalised to allow civilian staff to monitor CCTV cameras and issue £120 penalties by post. The fine would be reduced to £60 if paid promptly but drivers who appealed could lose the right to pay at the lower rate.

At some junctions, authorities could use existing CCTV cameras that catch drivers who stop on yellow boxes or make illegal turns. In others, extra cameras would have to be installed.

The new powers are expected to be included in a London local authorities Bill, due to be published in November. London Councils, the body that represents the 33 London boroughs, is supporting TfL’s proposal.

Nick Lester, director of transport at London Councils, said: “This will bring enforcement to an area where there isn’t any enforcement at the moment. Keeping drivers out of cycle lanes will encourage more people to cycle because there will be a greater perception that it is safe to do so.”

He said councils had already demonstrated that they had a better record of enforcing minor traffic offences than the police. In the year to March 2006, 12 London councils issued 389,000 penalties for stopping in yellow boxes and other traffic offences. “London authorities do eight times the enforcement of moving traffic offences as all the police in Britain put together.”

He said that cycle boxes were designed to allow cyclists to get in front of vehicles and be more visible to drivers. A high proportion of cyclist deaths and injuries result from drivers turning left without seeing the cyclist on their nearside.

Jenny Jones, green transport adviser to Ken Livingstone, the Mayor of London, said: “I find it infuriating that police are not using the powers they have. Far too many motorists ignore the white lanes marking out cycle lanes and they need to be seen to be punished. Better enforcement will give people, particularly women, more confidence that they will be protected if they take up cycling.”

But the AA said that many cycle lanes were poorly used and ignored by cyclists themselves. Paul Watters, its head of transport policy, said: “We would accept some surveillance on the busiest cycle routes if there was a thorough review of all lanes and those which were not working were removed. Authorities must exercise discretion because drivers may need to go into cycle lanes briefly to keep traffic moving. In city traffic, a minor misdemeanour has to occur sometimes for common sense reasons.”