HAVING had the same problem as Mr Key (' Killer cat woe', Letters, December 16) with not just one cat, but several, tame and fierce, every known method failed to keep the birds safe and our garden free of cat dirt.

Then we bought a battery-operated cat chaser.

It is harmless, just sends out ultrasonic sound, covering a 30-foot radius or 500 square feet. It can be bought by mail order from Renwood Ltd, order line 0871 210 7002 catalogue number M2055, for £29.99 plus postage.

It sounds very expensive, but after having spent a lot of money on useless deterrents, including plastic mesh to cover all flower borders which did not help the birds, we found this to be the best solution.

Harmless and humane, the cats simply don't like the sound, which is undetectable to the human ear. They turn tail and run.

Mrs A Clark,

Auster Bank Road,

Tadcaster.

Updated: 11:18 Tuesday, December 21, 2004