Fire control received calls shortly before midnight.
A spokesperson said: ‘Fire engines from Buckfastleigh, Ashburton and Ivybridge attended the incident alongside a water carrier from Plympton.
’On arrival crews confirmed the large barn measuring approximately 25m by 25m was well alight.
‘Crews got to work with jets and light portable pumps, utilising the local hydrant.
‘The barn has been completely destroyed by fire.’
Ashburton Firefighters later posted pictures from the scene of the fire and said: ‘This morning at around 12:30am ourselves along with Buckfastleigh Fire Station, Ivybridge Fire Station and a water bowser from Plympton Fire Station were alerted to a barn fire on the outskirts of South Brent.
‘The barn been very remote at the top of a steep grass field meant that crews had to use many lengths of hose￼ and a light portable pump in the middle to get water to the fire.
‘Using Ashburton’s appliance as the main pump Ivybridge, buckfastleigh and the water bowser started a water relay from the nearest hydrant.
‘Crew attacked the fire with two 45mm jets, after a few hours the fire was extinguished. Buckfastleigh fire station returned in the daylight hours of this morning to check for hotspots.’