All dogs are to be compulsorily microchipped so that their owners can be more easily traced under a crackdown on dangerous dogs. Under the scheme a microchip the size of a grain of rice is injected under the skin of the dog between its shoulder blades. The chip contains a unique code number, the dog's name, age, breed and health as well as the owner's name, address and phone number. When the chip is read" by a handheld scanner the code number is revealed and the details can be checked on a national database. The measures will be set out by the home secretary, Alan Johnson, who will point to rising public concern that "status dogs" are being used by some irresponsible owners to intimidate communities or as a weapon by gangs. If the scheme were made compulsory owners would face a fine for failing to microchip their dogs.