It's a legal requirement for all dogs over the age of eight weeks to be microchipped

All dogs over the age of eight weeks must be microchipped and their registered details must be kept up to date. Microchipping your pet gives them the best chance of being identified and returned to you if they become lost or stolen.

Dogs Trust and Blue Cross are currently offering free microchipping. 

Updating your dog's microchip
If you move or change your telephone number it is important to tell the database company so they can update their records. You will also need to arrange for the details on your dog's microchip to be changed if your dog is sold or given to a new owner.

You will need to contact the database company where the chip is registered to update the details (please note that there may be a charge for this). If you don't know which database company this is, you can contact the person who microchipped your dog, the Animal Welfare Officer or an authorised microchip implanter can check this for you.