The old gas holder in New Southgate

I am really very fond of these old Victorian structures. For such an every day type of need the Victorians managed to make them quite elegant.
Basically these holders stored domestic gas. Inside the outer, metal structure was another structure which, as gas was used or replenished rose and fell. There were water tanks in between at various stages which stopped air entering the system and igniting. Clever people those Victorians.
Since the advent of natural, North Sea gas there has been no need to store gas and a lot have now been demolished although preservation orders are being applied to many of the remaining ones.
In Dublin and London lots have been turned into flats.