British police and highway authorities are using undercover trucks to catch truckies driving dangerously.

Highways England is deploying three Mercedes-Benz Actros tractor units after a successful two-year trial, using just one tractor unit, resulted in 5400 truck drivers being booked for various unsafe driving offences.

The tractor units, each fitted with wide-angle cameras, will work in combination with police cars – mingling-in with other trucks to get close enough to offenders to capture evidence on camera of unsafe driving behaviour. The following police then pull the offenders over.

The first unit travelled around 160,000 kilometres on motorways and major trunk roads, spotting an average of one driving offence every 27kms.

The drivers had allegedly committed over 6500 offences – almost half of them involving the illegal use of mobile phones while driving….despite the latest UK statistics showing that mobile phone use is a factor in an average of two roads deaths every month.

One driver was found to have sent 10 replies to 10 texts within an hour, another was seen trying to put toothpaste on a toothbrush as he drove…and one truckie was caught steering with his knees while he ate his lunch….and used a mobile phone.

Another was caught making notes on an A4 pad while travelling along a major motorway.

Over 1200 drivers stopped weren't wearing seatbelts, 331 were speeding and 310 were allegedly not in proper control of their vehicles.

While 537 drivers were given verbal warnings, over 1000 were required to attend a driver education course and there were 194 prosecutions for serious offences.

The three new undercover trucks have had their speed limiters deactivated, so they travel up to Britain's 112km/h national speed limit. They have flashing lights installed in case of an emergency.

Highways England head of road safety Richard Leonard says: "We've found that the vast majority of drivers are sensible behind the wheel, but a few have got into bad habits – or are simply ignoring the law and putting themselves and others at risk.

"That's why we've funded these unmarked trucks to continue to target dangerous driving on England's motorways and major A roads, improving safety for everyone."

Leonard says that Highways has been "impressed" with the impact the initial undercover truck has had on improving safety.

Last year, the UK Government doubled the penalty for drivers caught using their phones at the wheel – with the fine now the equivalent of $NZ386.