This is no dumb box and the complexity of achieving the screen has been blamed for the delays - the extension was meant to be complete in time for the 2012 Olympics - and the spiralling costs (from £215 million to £260 million).

The entire screen acts as a slightly flexing net, so avoiding the need for ugly expansion joints common to most workaday brick architecture. The new sophistication is evident in the perforated brick veil made up of pairs of specially made bricks joined at the corners by dowels. “One thing with different atmospheres but the same organism.” The effect of the concrete has been softened by matching it with joinery, such as the elegant timber bench that runs around the edge of the new members’ room: “The most important challenge was to make it all feel like one building,” says Jacques Herzog. The scabbed concrete of the “as found” spaces approaching The Tanks has been extruded upwards with new concrete that is pleasingly raw, while visitor navigation has been improved by devices such as a giant internal slot uniting each of the gallery floors (echoed in miniature by open slivers either side of the treads on upper staircases). Revisiting Bankside has given the architects the chance to graft new thinking onto old stock. Tate director Sir Nicholas Serota argues that it is unprecedented for a museum to employ its original architect for a later extension. Herzog & de Meuron created the original Tate Modern at the outset of their career and in the years since 2000 they have learned to build museums worldwide that successfully marry adventurous architecture to good hanging space. Better than the existing museum building, where galleries can sometimes be gloomy and circulation tortuous.

New West End Company BRANDPOST | PAID CONTENTĪrchitects Jacques Herzog and Pierre de Meuron / Alamy.

Tate modern tate modern oil tank walls