There are four breeds of dog that are illegal to own in the UK. If you own one of the four illegal dogs there can be consequences.
Owning one of these dogs can result in the police taking the animal away from you even if it is not acting dangerously and there has been no complaint about it. Owning one is a criminal offence punishable by an unlimited fine and up to six months in prison.
It is worth remembering that whether your dog is a banned breed will be determined by an expert based on what it looks like. If a police or council expert judges that your pet matches most of the characteristics of a pit bull terrier, for example, then it may be deemed to be of a banned breed.