Dog Identification The Control of Dogs Order 1992

This mandates that any dog in a public place must wear a collar with the name and address of the owner engraved or written on it, or engraved on a tag. Your telephone number is optional (but advisable). 

Compulsory microchipping of dogs

It is now a legal requirement to have your dog microchipped in England, Scotland, Wales and Northern Ireland. All dogs must be microchipped by the time they are eight weeks of age and registered with a database compliant with the regulations, such a Petlog. All breeders will need to microchip their puppies and register themsleves as the first keeper of the puppy, before they are transferred to a new keeper.’The new keeper will also be responsible for updating the microchip with their details