A pay as you go model seems reasonable in principle, but the devil will be in the detail. In theory the information being gathered is public already. I could fo

A pay as you go model seems reasonable in principle, but the devil will be in the detail. In theory the information being gathered is public already. I could follow someone round the public highways if I wanted to. But having everyone’s movements in one big database obviously presents huge problems. The UK has no written constitution, which has its advantages sometimes, but could be a problem here. What we have instead is institutions. So we must hope that one of them steps in and puts limits on how this can be used.