http://www.caernarfonherald.co.uk/caernarfon-county-news/local-caernarfon-news/2012/04/19/criccieth-dog-owner-calls-for-tougher-controls-after-vicious-attack-88817-30789379/
“The owner of a dog which is dangerously out of control in a public place, or any premises where it should not be, is committing an offence. A dog is considered to be dangerously out of control if it injures a person or behaves in such a way that would make a person believe it might injure them.
“This may also apply where a dog attacks and injures another dog or the owner of that animal believes that they may be injured by intervening to protect their pet."