Firefighters say lives could have been at risk after arsonists started a fire in a field in Sunderland.
A total of 17 firefighters were called to tackle the blaze, near Willow Fields Community Primary School in Witherwack.
The alarm was raised at about 6pm, today, and it took crews more than an hour to get it under control.
A farmer was also called on for his help to plough a trench to stop the fire from spreading to nearby fields.
Watch manager Steve Bewick, from Fulwell Fire Station, said: “The fire was quite widespread when we arrived.
“With the wind direction constantly changing, it would have spread quite quickly.
“If there had been any kids in the field ,it would have easily trapped them.”
It is the first fire of this size the crews have dealt with since the start of the summer holidays, and firefighters are urging youngsters to think about the dangers they are putting themselves or others in by setting grass ablaze.
Watch manager Bewick added: “This is the first major field fire we have had since the school holidays started. We can’t say it enough, just how dangerous setting grass alight can be.”
The fire is said to have covered an area of 200-300 square metres.
No one is believed to have been injured in the blaze, which is believed to have been started deliberately.
Police were also called to the fire, and are now investigating.