Police are treating a blaze which saw seven vehicle transporters go up in flames as arson.
Emergency services were called to the fire at commercial premises in Geddington Road, Corby, at about 11.30pm last night (Sunday).
Police closed a number of roads in the area while eight fire crews tackled the blaze.
About 40 firefighters helped bring the fire under control by 2am, but some remained on the scene until about 7.30am today.
An investigation is under way and police are appealing for anyone who may have seen anything suspicious in the area around the time of the fire, or have any information about it, to contact Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 or use the anonymous online form at www.crimestoppers-uk.org.