Fluid movements: The Sasha Waltz dancers in full flow, performing Purcell's Dido And Aeneas in the water tank.

This is the star of the latest dance spectacular at Sadler's Wells Theatre - a 30ft by 11ft tank that weighs almost a ton.

The tank - filled with 7,500 gallons of chlorinated warm water - is the setting for 17 dancers from Berlin's Sasha Waltz And Guests to perform to the operatic accompaniment of Purcell's Dido And Aeneas.

It can accommodate seven dancers at a time, although in the show??s 20- minute prologue all 17 are submerged at some point.

Dancer Manuel Alfonso Perez Torres said: "It gets crowded but I think it creates a beautiful picture. We're not swimming and we're not dancing, the bodies are moving and floating and the water creates a peculiar and powerful quality of movement."

He said the hardest thing was not being able to hear the music being played by the orchestra.