Under an enormous canopy upheld by two cranes, Jethro Tull are playing in front of 50,000 fans, flanked by giant screens relaying the action via their own unique video system, Tull-A-Vision.

Most people think of Jethro Tull as a prog rock band with a flute, but this is an unfair assessment. All it takes is a bit of time, with three albums picked at random, to realise that Jethro Tull has ...