Thornton's career has been full of surprises.
Date of birth: 28 Oct 1972
Place of birth: Cleveland
Main trainer: Robert Alner
2002-03 wins: 62
2001-02 wins: 54
2000-01 wins: 54
1999-00 wins: 66
He started out as a teenager at Arthur Stephenson's yard in the north-east of England.
And although the death of the trainer in 1992 was an undoubted blow, Thornton was champion amateur jockey at the end of the season.
When a switch to Kim Bailey at Lambourn failed to produce the expected success, he changed his style of riding.
And within a six-month period, Thornton had bagged two of racing's biggest prizes.
He won the big Christmas race at Kempton, the King George VI Chase, on See More Business in 1997.
Then in March 1998, he landed the big one having picked up the ride on outsider Cool Dawn, who duly obliged in the Gold Cup - Thornton's last Festival winner.
Racing has a habit of bringing people down unexpectedly, and two months after that victory Thornton was sidelined with a broken leg.
That injury kept him out for four months, and a leg infection at the start of 1999 meant he missed several weeks.
However, he bounced back with victory in the 2001 Scottish Grand National aboard Gingembre and has ridden more than 50 winners in each of the last three seasons.