Stephen Sackur talks to Francis Rossi, guitarist, singer and founder of the band Status Quo - one of the most popular and durable acts in the history of rock and roll. He's turned the old mantra 'live fast, die young' on its head; he's lived fast and just kept on going. The music business has changed beyond all recognition in the last 40 years - how come Status Quo are still rocking all over the world?