The latest generation of TV licence detector vans is about to hit the streets - and undercover investigators are confident they will catch more people than ever.

The vans, which arrived in Brighton yesterday, are the tenth new model to be unveiled since 1926 and are the first to be designed with removable branding.

That means investigators can peel off the labels which could give the game away during covert crackdowns on licence dodgers.

They are powerful enough to tell if a television is in use within 20 seconds.

Staff are also happy to be driving much sleeker vehicles than earlier models, which had to carry huge, clunky aerials on their roofs.

The first vans were produced 77 years ago and subsequent models emerged in 1938, 1952, 1958, 1962, 1970, 1984, 1990 and 1998.

They are now white and look little different from the many other white vans on the roads.

Last year TV Licensing caught 1,497 people watching television without a licence in Brighton and Hove.

TV Licensing spokeswoman Vanessa Wood said: "Once the television is detected, the equipment - which works from up to 60 metres away - can pinpoint the actual room the television set is in.

"However, the technology is so secret that even the engineers working on different detection systems worked in isolation. Not even they know how the other detection methods work."

Anyone caught without a licence is likely to be fined up to £1,000 - and investigators are promising no mercy, especially as they can now patrol the streets unnoticed.

Ms Wood said: "These new vans really are a case of 'now you see it, now you don't'.

"By having the option of being able to remove the TV Licensing logo, licence-evaders won't know we're in the area unless we want them to.

"Fifty years ago you could spot the TV detector vans coming a mile off as the aerial on top was as wide as the van."

The new vans use GPS satellite technology to track down target addresses.

This means TV Licensing workers will be able to precisely target individual homes using up-to-the-minute information from a database of 28 million addresses.

For more details about buying a licence, which costs £116 for a colour television, or the concessions available, call 0870 241 5590 or see www.tvlicensing.co.uk.