Cambridgeshire police uncovered a cannabis farm during a raid in Ramsey yesterday (Sunday).
Officers searched two trailers in Middle Drove, Ramsey Heights, where they found an estimated £45,000 worth of cannabis.
They also seized what they believe to be two stolen trailers.
A spokesman for Cambridgeshire police said: "At about 3.20pm on Sunday officers discovered more than 40 cannabis plants in Middle Drove.
"As well as the plants they found containers of the drugs which had already been harvested. The combined value of the crop is an estimated £45,000.
"An investigation is ongoing. No arrests have yet been made.
"Anyone with information regarding this incident should call police on 101 quoting 35/32848/19 or visit www.cambs.police.uk/report. Alternatively, contact Crimestoppers, anonymously, on 0800 555111 or via www.crimestoppers-uk.org."