MOTORIST Joanne Berry is being driven to despair - because her car thinks it is an aeroplane.

The 1998 Toyota Avensis was her pride and joy when she bought it in April last year. And any fears she might have had about the car's reliability were allayed because it was still under warranty.

However, since then she has been plagued with problems caused by the remote central locking system - and according to the makers it is because of aircraft overhead.

Each time the problem occurs she has to use the key manually, which in turn means the security alarm goes off every time she opens the door and continues blaring for up to a minute.

So far, she has had to make the 28-mile round trip to the Knaresborough dealers seven times to get the system reset.

"It's frustrating, inconvenient and, according to the garage, caused by aircraft using the same frequency as the key," said Joanne, a 44-year-old veterinary receptionist who lives in Tholthorpe, near Easingwold, North Yorkshire.

"It means either leaving the car unlocked or using the key manually and setting off the alarm - and that's not popular with neighbours."

She added: "The attitude of Toyota, apparently, is that it's something the customer has to put up with."

A spokesman for Toyota insisted that all car manufacturers were required by law to use a certain frequency as part of an EC anti-theft directive.

"In using that particular frequency there are instances where certain other radio transmitters can interfere with this signal.

"On these rare occasions the remote-controlled central locking will not work," he said.

He said the key should not normally need resynchronising and that the problem is highlighted in the car's handbook, which suggests checking for nearby transmitters such as radio stations or airports.

He apologised for any inconvenience to customers and added that the Radio Communications Agency in the UK was pressing for the legislation to be amended so manufacturers could use a different frequency.