Firefighters battled through the night to tackle a barn blaze in Folly Lane, South Holmwood.
The fire broke out at about 2pm yesterday at Folly Farm, with about 100 tons of hay going up in smoke.
Surrey Fire and Rescue received "multiple calls" from the public alerting them to the incident.
A Dorking firefighter said: "We are allowing the fire to burn itself out.
"We are keeping a watching brief on it to make sure it does not spread."
