[pilingual]

There are two key concerns:

1. Data is retained by a handful of companies. If it is leaked, you'll have a lot of information on people that is suddenly fair game for anyone including insurance companies, PI, home invaders.

2. In the US, I'm not concerned about local government as much as federal when it comes to the fourth amendment. Suppose you have a rogue potus. He sends the national guard in to Atlanta, Chicago, and Downingtown to take over the systems of these companies. Now you say, "well I'll just remove my license plate!" But these companies are cataloguing make, model, color, bumper stickers, dents; so you can take off your plate in a situation like that but they are going to still be able to track you with a high degree of certainty. People were shocked by South Korea declaring martial law -- we've become so spoiled taking these essential laws for granted. (Sorry I don't know enough about British law.)

If they don't send all license plate data to the internet there isn't an issue. But they do.