Effectively a tax on the many to protect against the few.
They're also proposing compulsory micro chipping at breeder level, although what precisely that is meant to achieve once a dog leaves the breeder I have no idea. There are multiple micro chipping organisations and not all vets use all of them, and if someone is a crap dog owner they probably won't take them to the vet anyway.
Some people may remember, that way back in the mists of time, there was something called a Dog License. It was compulsory but it was scrapped in 1987 because most people just ignored the requirement and felt paying 37p at the Post Office for a piece of paper was pointless.
This is what you can guarantee will happen with the compulsory insurance ideas when it comes to those that own dogs that have been constantly prodded in their balls to make them vicious, just like people that drive a car without insurance.
I also wonder how long it will be before we hear about a burglar suing someone he tried to rob for damages because their free roaming guard dogs did their jobs.
Incidentally, and as an aside, dogs aren't inherently dangerous. It's a combination of humans training them to be, and other humans not realising how to make a dog submissive through body language alone.