"Gas pressure is maintained by gasometers, which work by gravity, so pressure will stay up until the gasometer is empty"
There is no gasholder infrastructure in the UK at all. All the gas in the pipes is all the gas we have.
They are all mothballed. None of them are in use any more and are usually listed, demolished (the 3 that sat next to my workplace went last year :( or they get turned into flats.
Of course I think that getting rid of them is a pathetically stupid idea. You cant underrate emergency capacity, but apparently someone thought that the pipes are enough. I remember hearing during the beast from the east that the pipe capacity was being pushed to its limits, I turned to look at the gasholders being demolished outside my window and thought I was in a sitcom.