The legislation on the welfare of pets and animals was consolidated into the Animal Welfare Act 2006. However, the legislation dates back to the 1930's.
The penalty for a breach is a maximum fine of £2,500 and/or imprisonment for up to 51 weeks.
Although there are provisions for disqualification from dealing in animals contained within the Act, these do not apply to offences of selling animals to under age purchasers. However, if it is considered that the act of selling the animal caused, or was likely to cause, unnecessary suffering to the animal, then the provisions disqualifying the seller from dealing in animals would be available to the courts.