A shed was deliberately set on fire in the village of Coates, just outside Whittlesey.
Firefighters from Whittlesey were called out on Wednesday at 9.08pm to March Road.
The crew arrived to find a fire involving a shed measuring 6 x 4 metres that had spread to a fence.
The firefighters used a hose reel to extinguish the fire before returning to their station by 10.40pm.
Anyone with information on how the fire was started should contact police by visiting www.cambs.police.uk to submit an online report or call Crimestoppers on 0800 555111.