At 8.31pm on Tuesday (26) one crew from Stanground was called to a fire on The Causeway in Thorney.
Firefighters arrived to find a fire involving a tyre on top of a speed camera. They extinguished the fire using a hose reel and returned to their station by 9.35pm.
The cause of the fire was deliberate. Anyone with information should contact police by visiting www.cambs.police.uk to submit an online report or call Crimestoppers on 0800 555111.