4. Olly Barkley
Barkley won 23 caps for England between 2001 and 2008, and such was his early reputation that he featured for England before his club debut with Bath.
A graceful left-footer able to play at fly-half or inside-centre, Barkley should have been a mainstay in the England midfield after the retirement of Will Greenwood.
The strange thing about Barkley is that it is hard to say where it all went wrong. He is not blessed with great pace, but kicked well from the tee and out of hand, was a fine distributor and hardly a defensive weakness. He remains one of the biggest mysteries of English rugby from the 2000s.