It used to be that you knew you were a true star when someone handed you an Oscar, or a Nobel prize, or a platinum disc for your latest album.

But today you can tell that you've made it in life when — before signing a contract to sing, or to make a speech — you demand that your dressing room be filled with a species of orchid found only in Tonga, or that nobody in the audience be allowed to wear black, and the organisers say: "OK".