Didn't they stop using them with the introduction of North Sea Gas back in the 70s? I know there are some still about and look like they are still serviceable, I maybe wrong!
The firm I used to work for produced bio-gas by anaerobic fermentation and the gas was stored, on site, in those gasometers before being sent to the boilerhouse for steam raising. Simplest way to store gas under slight pressure.
One of the London test cricket grounds has one in the background (Lords?) it was still visible the last time I saw cricket from there. I was surprised as I though they had all gone . Or prehaps I was watching a replay of an old match with out realising.
As has been mentioned in the articles,these are not gasometers (i.e. they do not measure gas) but they are gasholders.
There are dozens, if not hundreds of them still around. A site a couple of miles from where |Ii live has three large gasholders, two contained within a frame and one of the free standing "spiral telescopic" variety.
The gasholders at the Oval are world famous. As Lords' has its Nursery End, so the Oval has its gasworks end. A well known actor who cannot be named for legal reasons (Ray Winstone) was once talking on a chat show about the sexual orientation of a fellow actor. "Yeah of course he bowls from the gasworks end. Everybody knows that".
We Surrey members call it the Vauxhall End. We don't admit to a gasworks! The Surrey Tavern is a famous gay venue in an old pub nearby. It is..er...at that end.