Dogs are classified as property under the Theft Act 1968 - meaning that a stolen dog currently is legally the same as a stolen bike.
Following the recommendation of the Pet Theft Taskforce, the Government stated that Pet Theft would be classed as a new criminal offence and added to the Animal Welfare (Kept Animals) Bill - the Bill has not been yet passed as law and disappeared from Parliament.
Please Contact you own Member of Parliament (MP) and ask them to support the Kept Animals Bill and bring it back into session so that it can proceed to become law.