Officers from North Dorset are appealing for anyone with information to come forward after 21 tonnes of fabricated steel was stolen from a trailer near Sturminster Newton.
The incident happened between 7.40pm and 10.40pm on Sunday, 13 January at Snashall Steels on Pulham Business Park, Pulham.
Offenders damaged fencing to gain access to the site and used a shunter truck belonging to the victim to move the trailer out of the yard.
Police Constable Gary Mitchell, of Gillingham police, said: “We believe the thieves transferred the trailer to their own vehicle which must have been parked a small distance away.
“The trailer is quite distinctive having blue fairing down the sides and the word ‘Gilliards’ on it.
“The steel is valued at around £40,000 and this crime has caused a considerable financial loss to the victim.
“I am particularly keen to trace the stolen property and speak to anyone who has been offered steel in strange circumstances, possibly for an unusually low cash sum.
“If anyone saw anything suspicious in the area of the business park or has seen this trailer since or they should contact Dorset Police as soon as possible on 101.”
Witnesses and anyone with information should call Dorset Police in confidence on 101 quoting incident number 14:51. Alternatively, call the free and anonymous Crimestoppers line on 0800 555 111 where mobile phone tariffs may apply.