Someone already compiled a list of the defunct cinemas from my childhood area. It makes for interesting but sad reading.
This is just in the Walthamstow area of London. (although the Savoy shown about half way down the page is actually in Leyton and was my local as a kid). As it stands now there is not a single cinema operating of any kind in the entire borough when there used to be half a dozen or so when I was growing up and twice that number when my parents were young. When Alfred Hitchcock was a young man (he was born and raised in this area) they even used to make films here.
Probably the saddest loss is the old Granada Cinema in Hoe St. That was a true picture palace with a sumptuous interior that seated over 2,600 people and presented live shows as well as films. The building still exists, just, but is in a terrible state and plans are afoot to demolish it just as soon as they can get around its historic building listed regulations. It will be a truly sad day for me when they finally knock this treasure down. Here's some more details on its history: