The current Law states that anyone found guilty of abuse towards an animal, MAY be banned from keeping animals ( making it possible that the offender can own animals again in the future and therefore could commit the same crimes). They could be fined up to £20,000 (although in reality it is around the £1000-£5000 mark) and the maximum jail sentence for acts of cruelty against animals is 51 weeks ( most offenders end up serving much less then half the time).
If an owner whos dog injuries another human, a sentence of upto 5 years can be applied, where as the maximum sentence for theft is 7 years.
If someone can deliberatly set out to abuse, harm or torture an animal, they should be seen as dangerous. If they can show this form of cruelty to an animal, what's to say they can't act this way to a fellow human being?