Anyone who wants to train a horse to run at any of Britain's Flat courses must have a licence to do so from the Jockey Club.
There are currently about 700 licensed trainers in Great Britain.
The elite trainers have first-class facilities with state-of-the-art equine pools and blood-monitoring equipment.
But many others have much smaller establishments although the competitive nature of Flat racing means the big prizes tend to be won by the bigger stables.
Many of the leading trainers have about 150 horses with Sir Michael Stoute's stable the biggest in Europe with pushing 200.