Detectives believe they have found Cambridgeshire's biggest ever cannabis farm - worth an estimated £1.75 million - at a property in Haddenham.
Officers executed a warrant, under the Misuse of Drugs Act, at a property in Hill Row on Thursday morning.
Four men have been arrested and are currently in custody at Parkside Police Station.
More than 5,000 cannabis plants, worth an estimated £1.75m, have been recovered and officers believe it to be the biggest cannabis factory ever found in the county.
Specialist teams have been at the scene conducting searches and forensic examinations.
Detective Inspector Craig Harrison said: “This morning’s raid is part of our ongoing work to tackle the production and supply of cannabis in the county.
“Today we have discovered thousands of plants and we believe this to be the biggest ever cannabis farm in Cambridgeshire.”
A 41-year-old man from Haddenham, a 24-year-old man from Huntingdon, a 29-year-old man from Huntingdon and a 40-year-old man from Warboys have all been arrested on suspicion of producing cannabis.