It could be the end of the road for some speed camera detectors, with a ban expected next year. But could their use just be driven underground?
Detectors have an audio and visual alert
MPs have voted to ban devices which detect speed cameras and guns. The Road Safety Bill was given an unopposed third reading by the Commons and sent to the Lords. It could become law in 2006.
It outlaws detectors that warn motorists as they approach working cameras and mobile speed traps.
Detectors which alert drivers only of fixed camera sites would remain legal.
The Bill says: "The government believes that devices which interfere with or detect the proper functioning of such cameras have only one purpose: to tell drivers when they can break speed limits and get away with it.
"This is unacceptable. It prevents the police from carrying out their duties, and is a danger to other law-abiding road users."
Penalties have yet to be decided on.
Devices which rely on Global Positioning System (GPS) technology to warn drivers of published camera sites are not included because they complement the government's policy to ensure that camera sites are visible and conspicuous to drivers, the Bill says.
The GPS detectors work by having a database with all the locations of the fixed cameras.
Fixed camera sites have to be highly visible
But it is the sophisticated radar-based detectors which are being targeted. They can tell which cameras are not "live" because they are decoys or have no film. Some camera sites are dummies because police rotate their resources.
As well as the fixed camera sites, there are an estimated 2,500 mobile sites which are also detected by these devices.
They are manned by police officers, who can also use speed guns and are not subject to the same visibility rules as the fixed sites.
So how do these devices work?
Car Parts Direct has sold nearly 11,000 Quintezz XT7000 radar detectors, which operate by picking up the frequency emitted by cameras.
For £199, a driver has a small device which emits an increasingly audible alert as the motorist gets closer to a working camera. It plugs into the car's cigarette lighter and also has visual alert.
The detectors also warn motorists of laser guns and mobile speed traps run by police.
Mark Cornwall, the boss of Car Parts Direct based in Derby, says he has a three-year contract remaining to supply these devices, and will be pursuing a £2m compensation claim from the Department for Transport.
"Our radar detector does exactly what a speed camera is supposed to do - it advices a motorist to check their speed and keep within the limits of the law," he says. "Radar detector users are 28% less likely to have an accident."
Many of his existing customers are from France or Ireland, where the devices are already banned. Similar illegal use will happen in the UK, he predicts.
"A motorist's desire to keep their driving licence is much stronger than the risk of being caught with a radar detector - sales will rocket as the ban gets closer."
But road safety groups have welcomed the ban. Aimee Bowen of road safety charity Brake says users of these devices are just trying to flout the law.
"Drivers already have a free mechanism in their car. It's called a speedometer. No-one needs these devices unless they have an ulterior motive, which is to break the law and put lives at risk."
Other European countries which have outlawed camera detectors include France, Belgium, Greece, Austria, Turkey, Switzerland, Luxembourg, Ireland and Norway.
But Spain has no ban, so Mr Cornwall predicts motorists may also travel there to buy them.