Police responded to reports from the public concerning suspicious activity at premises in First Avenue, Hove, just before 2.40pm on Wednesday (11 November).
A number of people were seen fleeing the location across neighbouring gardens leading to multiple reports from concerned members of public.
Police attended and discovered a significant cannabis cultivation site in a former hotel. There are estimated to be in the region of 2500 plants across several floors of the premises.
A 38-year-old man has been arrested on suspicion of allowing a premises to be used in the production of a Class B drug and has been released pending further investigation.
Enquiries are ongoing and officers are appealing to anyone who has noticed recent suspicious activity in the lower First Avenue area to report it to us quoting reference 798 of 11/11.