LONDON – A tracking chip for Spot? In a country where guns are tightly controlled and even carrying a kitchen knife can bring prison time, some thugs use dogs to menace their victims. Now the British government is proposing that dog owners be forced to get microchips and take out insurance for their pets.

Postal workers were delighted by the proposal, announced Tuesday. But opponents complained it would impose a financial penalty on innocent pet owners, while criminals with violent animals would simply ignore the law.

The plan risks “penalizing millions of law-abiding dog owners with the blunt instrument of a dog tax,” warned opposition lawmaker Nick Herbert.

Home Office Secretary Alan Johnson said there was “no doubt that some people breed and keep dogs for the sole purpose of intimidating others. It is this sort of behavior that we are determined to stop.”

Microchips would help trace the owners of dogs involved in attacks, while insurance would mean that victims of dog attacks are compensated for their injuries, he said.

Hospital admissions and court cases involving dangerous dogs have been on the rise in Britain, a nation whose canine population numbers 8 million. In London, court cases have climbed from 35 in 2002-2003 to 719 in 2008-2009. About 6,000 postal workers are bitten each year.

Dog attacks that have killed at least five children since 2006 have also kept the issue in the headlines. But Ryan O’Meara, chief editor of K9 Magazine, said the government’s plan would not solve the problem of dangerous dogs attacking humans.

“There is nothing in this that is preventative,” he said. “If you put a chip in a dangerous dog, the bite will hurt you just as much.”