Some of these look like organised displays, but others probably aren't. Unlike in Australia, anyone can buy fireworks here and set them off, which is why you get bottle rockets whizzing horizontally across parks and almost knocking people over and such; and apparently the casualty departments of hospitals are doing a roaring trade as well.
One thing that I found slightly surprising: the English really get into Halloween (which I thought was an American thing, at least in its modern incarnation). There were carved pumpkins everywhere, and I saw a number of people dressed up for the occasion. (And not just little children in pumpkin suits either; there was one woman walking down Oxford St., attired in green face paint and a witch's hat. Not the sort of thing you see in Australia much.)
Interesting. Growing up half-English in Australia, Halloween wasn't something I/we were particularly worried about celebrating, and when an overseas friend asked me just the other day if it was celebrated much in England or Europe, I said "no, I don't think so."
I stand corrected...