If anyone is curious "The British Security Industry Association (BSIA) estimates there are between 4-5.9 million cameras"
Given the population, there are actually more cameras per UK citizen than there are per Chinese citizen.
The vast majority either do not work, or are privately owned and when enquired about (difficult in itself as there are so many parties to contact once the owner is identified, and they likely do not have direct access and need to speak to someone else) have extremely useless retention periods that meant no footage survived enough time to request it.
The IRA (or their reactionary counterparts) are who you should blame for the amount of CCTV in London, but it all comes from the same place. If it wasn't them, it would have been something else.
My first memory of surveillance in any kind of large-scale was in the early 1990s, well before Tony Blair. It was when the Met police put up the "Ring of Steel" around the centre of London to stop the volunteers blowing things up.
Anyway, too much surveillance bad. Unless they use it to find your phone, in which case too much surveillance good. One might think it's somewhat of a nuanced issue!