What Kind of Psychopath Wants to Own a Savage Dog?

My lovely, sweet, affectionate, harmless Cocker Spaniel was savaged yesterday by a bull terrier-type dog let off its lead without a muzzle in a public park.  Fortunately my young, strong, brave and fit son was the one walking him at the time and managed to wrestle with the beast and prize open its jaws. Had its walker been anyone less strong and brave our Cocker would almost certainly have been killed; all its owner did was stand and watch, and his beast had already inflicted multiple deep wounds with blood gushing out of them in the minute or two it took my son to drag it off.   Three visits to the vet for treatment so far, and many more to come at horrendous expense before he is finally signed off I should think.

Browsing the internet we discover that other harmless little dogs suffer similar attacks on a daily basis and nothing much can be done about it because no criminal offence has been committed so the police won't be interested. 

Only someone who actually admires and enjoys savagery could possibly want to own such a breed. If we can manage as a society virtually to criminalise smokers, why for God's sake can't we make the owners of savage dogs suffer for wanting to inflict them on the rest of us?  Why not add an element to Council Tax for all households with dogs, on a sliding scale from modest for harmless little breeds to punitive for the breeds that most frequently attack? Unlike the old dog licence this would be cheap and easy to administer and would bring in some badly needed revenues as well.