A search of an isolated farm in North Chailey uncovered 1,500 cannabis plants with a potential street value of at least £1m.
Detectives and uniform officers from Sussex Police executed a drugs warrant at Warrenorth Farm, on the A275 East Grinstead Road at 9.15am today (Wednesday February 26).
The plants were discovered in a specially adapted outbuilding at various stages of growth.
Two men and two women were arrested at the address on suspicion of being involved in cannabis cultivation and are currently in custody for interview and further enquiries.
Detective Inspector Gavin Patch said; “Although our examination of the building is at an early stage it is already clear that this is one of biggest such sites we have seen for some time.
“This was an intelligence-led operation, following up information we received. If anyone has any suspicions about such activity we ask them to call us via 101 or email email@example.com”