Trapped by the biggest yellow box in London

It is big, it is yellow and it is a licence to print money.

Freshly painted, this box junction is designed to speed up London's traffic, its enforcers claim. But its critics suspect it has the specific aim of parting motorists from their hard-earned cash.

The box is in High Holborn, near the intersection with Southampton Row and Kingsway.

Motorists who stop in it, and are spotted by a newly erected camera, face a £100 fine, reduced to £50 if they pay within 14 days. So far, so legal. However motorists complain the box, which stretches some 90 feet westwards from Procter Street to Holborn Tube station, is too big - with the result that hundreds of drivers who are not causing delays are being caught.

Camden council is not complaining: the box generates up to £60,000 a month.

Normally, yellow boxes are put at junctions to stop static traffic blocking the road for vehicles moving in a different direction - but at High Holborn the road is part of a one-way system, with all vehicles heading west.

An Evening Standard survey found that in only two hours one lunchtime this week, 158 vehicles, including two police cars, stopped illegally in the box. In the first hour, 105 vehicles were stationary in the yellow zone.

Of these, 20 were black cabs, seven were buses and one was a police vehicle-In the second hour 53 vehicles were at a standstill in the grid.

Black-cab drivers are leading the protests, accusing the authorities of coming up with "the perfect scam"

Bob Oddy, chairman of the Licensed Taxi Drivers' Association, said: "It seems to be a money-making exercise. Most of it is on a section of normal roadway, not at an intersection. Our drivers are dumbstruck. They can't work out why it needs to be 90ft long."

His colleague Richard Massett said it was almost impossible to avoid getting caught in the box. "This is likely to bring the whole scheme [to enforce yellow boxes] into disrepute," he said.

Taxi driver Thomas Hunt, from Islington, said: "They can have a box junction but it does not have to be as extended as that. I've heard of people being fined but it's not fair because you can be away from the junction and yet still in the box."

Bus drivers have also complained about the size of the zone and London Buses has called for a site meeting with Camden engineers.

The Highway Code states drivers should only enter a yellow box if their exit is clear, or blocked only by oncoming traffic if they want to turn right. Ahead of the High Holborn box, signs indicate the area is a controlled zone with no loading at any time.

Since July local authorities have been able to enforce traffic rules as well as the police. Camden is one of several boroughs to take advantage of the law change. A Camden spokesman estimated about 600 drivers a month were caught at High Holborn. He said: "It was put in, after consultation with Transport for London, on safety grounds and to keep traffic flowing at a very busy junction.

"We get accused of trying to make money by people who get caught. But the onus is on drivers to be aware of the traffic signs." He said the box had been there for some years, but was repainted in the summer.