Abstract: An inground storage tank, particularly for storage of oil and inflammable liquids comprises a concrete wall enclosing a steel shell and surrounded by a water pervious sheet of plastics material and a mantle of gabions. The gabions allow water drainage to drainage ducts in the foundations of the wall. The steel shell has a conical roof structure welded thereto and a layer of earth on the roof. Columns within the shell support the roof. The tank is constructed by constructing the foundations and drainage ducts and then building a portion of wall, and shell, filling the shell with water, surrounding the wall with plastics sheet and gabions and repeating these steps until the required height is reached. The roof is then secured to the shell.