Tessa Jowell praises artist Juan Munoz

She said: "It is a department which has an enormously important role through the institutions it funds in shaping a sense of national identity and as a major contributor to quality of life.

"I think there are two central principles - access on the one hand and the creation of excellence - and the underpinning of excellence - on the other.

National institution

"Here we are on my first day at work in one of the major national institutions which incorporates both."

Munoz visited many cities to see view people's working environments as he created Double Bind over a 12-month period.

From above visitors will see just a pair of lifts emerging from the ground, which is scattered with a series of square holes.

But from below those looking into the holes can see the figures trapped in a world of ventilation shafts and cooling systems.

Munoz said: "I'm probably only the second artist in the world to work in such a big space.

"I'm very happy with it, I think it works. I'm sure the spectator will be surprised."

His piece replaces the towering sculptures by Louise Bourgeois which stood in the Tate Modern during its first 12 months.