FEWER than one third of fixed speed cameras in Scotland are actually switched on and catching offenders, new figures reveal.

Of the 173 devices monitoring drivers on the country’s roads only 50 (29 per cent) are active.

Data released by 36 of the 45 police forces across the UK found that four – Cleveland, Durham, North Yorkshire and Northampton – have no fixed speed cameras recording at all and 13 have fewer than half actively catching speeding drivers.

The figures cover all police fixed speed cameras, but not the mobile devices forces also use.

All forces and speed camera partnerships that responded said they deployed regular mobile speed cameras across their areas.

They also said they regularly review which fixed cameras are turned on.

Some motorbike riders have reportedly been getting away with speeding because many traffic cameras fail to detect them,

Just 41 riders were caught by average speed traps in Scotland last year compared to 14,594 cars.

It was reported that a limited number of devices can photograph number plates for motorcycles, which are on the back of the vehicle, because the cameras are set to oncoming traffic.

Alan Thomson, of West Safety Camera Unit – comprising 13 councils – said: “Not all average speed cameras have rear-facing capabilities but a significant number do.”

A Transport Scotland spokesman said: “All permanent average speed systems have the capability of front and rear-facing detection.

“Enforcement strategy is decided by the respective safety camera unit.”

It has been reported mobile roadside camera vans have netted £3.6 million in fines from around 36,000 speeding drivers since 2013.

Three locations policing the same stretch of road – the busy A74(M) motorway through Dumfries and Galloway – are the most lucrative.

One van, situated at Kirkpatrick Fleming, recorded 7310 speeding offences. And a few miles north, near Beattock, the second-highest number of offences was recorded by a different van with 5187.

One of the most contentious series of fixed cameras were installed on the A9 in October 2014.

Some motorists feared the 27 cameras between Dunblane and Inverness would cause traffic problems but the number of drivers caught speeding fell dramatically as well as the number of accidents.

Road safety charity Brake described the figures showing the inactivity of many Scottish fixed speed cameras as concerning and called for all cameras to be switched on, while AA president Edmund King said the high number of inactive cameras was down to pressure on budgets.

The Northamptonshire force said it turned its cameras off in April 2011, but has left the structures in place to deter speeders.

Staffordshire Police have 272 fixed cameras across their patch, but just 14 of them are active, while the Derbyshire force operates 112 cameras with just 10 of them catching speeders.

The forces with a quarter or less switched on are West Yorkshire (25 per cent), Kent (25 per cent), South Yorkshire (24 per cent), Greater Manchester (24 per cent) and Cheshire (17 per cent).

City of London, the Metropolitan Police/Transport for London, Lancashire, Nottinghamshire, Suffolk and Northern Ireland said all their fixed cameras were active.

West Midlands Police, who announced in 2013 that their old speed cameras were being switched off, said they now had eight new average speed cameras.

A spokeswoman for the National Police Chiefs’ Council said the decision to use cameras was “an operational matter”, adding that “all forces have individual responsibility for their use of speed cameras”.

Motoring groups warned drivers not to gamble by speeding through cameras hotspots in the hope they are switched off.

They warned that police still used many mobile devices and also that average speed cameras were also frequently used to catch motorists breaking the law.

Steve Gooding, director of the RAC Foundation, said: “It would be a dangerous and foolish driver who was tempted to speed because they thought they’d get away with it.

“Not only are cameras routinely moved between housings, police also use mobile cameras, while several hundred miles of British roads are now being monitored by average speed check systems.

“The majority of the public back the use of speed cameras, but the location and effectiveness of the devices should be the subject of regular scrutiny.”

The president of the AA echoed the warning and said tight budgets meant many of the cameras were switched off.

Edmund King said: “Many of the empty yellow cases are due to cuts in road safety grants and the fact that digital cameras, although more effective, are very expensive.

“It is also reflective of the fact that proceeds from cameras are no longer allowed to be ring-fenced to be reinvested into yet more cameras as now all the money goes to the Treasury.”

He warned motorists against gambling on a camera being inactive.

He said: “Drivers who play Russian roulette with fixed-site speed cameras are playing a dangerous game. Our advice is stick to the limits rather than gambling on the yellow boxes.”

Neil Greig, spokesman for the charity IAM RoadSmart, which campaigns to make roads safer by improving driver and rider skills, said it believed all speed cameras should be active.

He said: “Drivers should be in no doubt that every yellow box they pass is active and police forces and safety camera partnerships should all be aiming for their cameras to be vigilant 100 per cent of the time.”

And Jason Wakeford, director of campaigns for road safety charity Brake, said: “A staggering 1,800 people lost their lives on British roads last year and speeding is a factor in thousands of crashes.

“Speed cameras are a proven, cost-effective way of reducing deadly collisions and so it’s critical they are operational.

“We are concerned to see figures which suggest so many are switched off and would urge they are urgently put back into action.”

However Claire Armstrong, co-founder of lobby group Safe Speed, which campaigns for more traffic police officers rather than speed cameras, said the investigation “proves police forces don’t believe in cameras”.

She said: “Forces are conning the public into thinking cameras are there for road safety because, if they really thought that, every single one of them would be on.

“They are a flawed road safety policy and the only way to truly improve that is with more traffic police officers on the roads.”

She added: “I am glad there are only 52 per cent working - and we’d actually like to see less.”