Gas holders, often referred to as gasometers, were once a feature of every town of any size in Britain. They are enormous structures yet, despite their size, are almost invisible – a part of the townscape which people simply don’t notice.

There are three main types of gas holder in Britain. The most familiar has a sectional storage tank which rises and falls on rollers inside a permanent lattice-type structure. In summer the storage tank is generally empty and the lattice structure stands vacant. In winter the tank is more often full and rises and falls – slowly – within the frame. The second most common type has a sectional tank which rises and falls in a spiral movement without the need of a fixed supporting structure. This type effectively disappears in the summer months, when the gas holder is empty. The third and least common type in Britain has a solid cylindrical exterior frame and an internal piston with a retaining disc which rises and falls. There is no visible sign of any change as the storage tank fills and empties. On some sites gas holders of two different types can be found together.

The discovery of gas in the North Sea in the 1970s changed the way in which gas was stored and delivered, and one result of this has been a gradual reduction in the number of gas holders around the country.