YOUR correspondent Mrs Susan Davy (Letters, February 4) rightly extols the virtues of microchipping pets, but I would offer a note of caution, since implants are permanent and not all chips are the same.

The effectiveness of a microchip is wholly dependent on the database with which it is registered. Since there is no money to be made helping desperate owners in a lost/stolen/stray situation, commercial databases will pay their way, inter alia, by selling pet owners details to marketing companies. And some vets will understandably choose to implant the chips which offer them the best financial incentive.

There is only one database, run on a non-profit making basis by the UK Kennel Club, which will not supply client details to third parties, which will never “cease trading”, and which offers substantial assistance in the event of a crisis. That database is PETLOG, and if readers are sensibly considering having their dogs microchipped then they are recommended to ensure that the chip implanted is PETLOGcompatible and that they register the details with PETLOG. For information on Compulsory Microchipping visit And if you subsequently move house – don’t forget to let the database know!

TONY CROWTHER, Bouvier Rescue, Southampton.