FTA:

Indeed, police cameras cover every in across the UK and China

Almost all cameras in the UK are privately owned and are not accessible to police unless the police request recorded data from the owners. There are police-controlled cameras set up in some city centers, stadiums, railway stations, etc, but that's about it.

The risk of private surveillance data being aggregated into public surveillance (e.g., by Flock giving the police access to its data streams) is real, but hasn't happened so far in the UK to any significant extent. We also benefit from the obsolescence of most of the installed base for most private surveillance tech (e.g., low-resolution CCTV recorded by video tape) in private businesses such as pubs and corner shops. That kind of thing can't ever be integrated without great effort, and small businesses are not eager to spend money upgrading such systems.