Forty horses were rescued from their stables after a fire broke out at an equestrian centre in Leatherhead.
Surrey Fire and Rescue Service said they were called to the blaze at the Pachesam Equestrian Centre in Randall Road at 2115 BST on Thursday.
A spokesman said the fire started in a barn and spread to nearby outbuildings. It is not being treated as arson at this stage.
Proprietor Linda York said everybody was shocked.
She said: "It looked like it started in the hay barn and quickly became a vicious and frightening inferno.
Risk of explosion
"We had nearly 40 horses here and there are probably now about 10 or so that are now homeless because their stables are razed to the ground.
"Every animal is safe and it's very fortunate that it happened when people were still around."
One theory is that some bales of hay stored in the barn combusted. More than 100 tonnes of hay were destroyed in the blaze.
An equestrian competition due to take place on Saturday will still go ahead, Ms York said.
A spokeswoman for Surrey and Fire and Rescue Service said crews were dampening down at the scene.
At the height of the fire, about 20 firefighters fought to contain the blaze and remove gas cylinders that were at risk of explosion.