YORK'S first "intelligent" bollard has developed another fault - and is once again letting anyone through.

The automatic rising bollard in Stonebow - meant to allow through only authorized vehicles such as buses and taxis - is again sinking into the ground when any vehicle approaches.

But council bosses say that two incidents earlier this year, in which first an ambulance and then a bus crashed into the bollard, were both caused by "driver error".

The bollard was installed by City of York Council in 2000 in an effort to prevent unauthorised motorists driving through Stonebow, Pavement and Piccadilly.

Cabbies could pay a charge for an electronic sensor to make it fall when they approached. New technology was also installed so that specific number plates could be recognised to activate the bollard.

But the Evening Press revealed last September the bollard had been lowering when any vehicle approached.

It sank into the ground when our reporter drove up on two different occasions. Taxi drivers who said they had forked out for special sensors to let them through complained the bollards had been letting anyone past, including boy racers who had heard about its failure.

The council said then there had been some "intermittent problems" with the bollard, which it thought had been caused by problems with the automatic number plate recognition technology, and it was "looking into the problem".

But 11 months later, the same problem is happening again. The bollard once more sank into the ground when our reporter drove towards it yesterday. Earlier this week, the bollard had remained firmly in the ground at all times, whether or not anyone was approaching it.

A council spokeswoman said there was a "minor problem" with one of the automatic sensors for the bollard and it had first been deactivated until the necessary part arrived.

But it was later allowed to work again until the part arrived, because it was still felt to act as a deterrent even though it sank down for everyone.

She reminded motorists that it was still illegal for unauthorised people to drive over the barrier and along Stonebow.

A First bus collided with the bollard in May, and an ambulance on an emergency call struck it in January.

First boss Peter Edwards said today he accepted the council's conclusions that driver error had been to blame. He said hundreds of buses went past the bollard without mishap, and it was a useful tool in helping to prevent unauthorized motorists going along Stonebow.

Updated: 11:06 Friday, August 05, 2005