More than 35 firefighters from across Somerset tackled a major heathland blaze at Crook Peak, near Burnham-On-Sea, on Monday afternoon.
Seven crews were at one point dealing with the fire on the northern side of the hill, which was alight for more than four hours.
Smoke from the blaze disrupted traffic on the nearby M5 motorway as motorists slowed down to see the fire, which had been fanned by gusty winds.
A Somerset Fire and Rescue spokesman told Burnham-On-Sea.com that it was believed a controlled fire in a nearby field had got out of control at around 3.30pm, leading to the dramatic scene.
Fire appliances had rushed to the scene, including two pumps from Cheddar, a water carrier from Bridgwater, a command support unit from Street, plus further pumps from Weston, Blagdon and Winscombe.
The spokesman added: “The fire was fought by crews using beaters and was finally brought under control at 7.35pm.”
“Damage was restricted to a large area of heath on the side of the hill. The cause was accidental spread from controlled burning being carried out by the National Trust.”