Detectives from Bexley are investigating an arson following a fire at Queen Mary's Hospital, Frognal Avenue, Sidcup.
On Tuesday, 18 August, at approximately 19:00hrs, police and the London Fire Brigade (LFB) were called to reports of a fire in a derelict maternity ward at the hospital.
The fire is being treated as suspicious.
A man was arrested on Wednesday, 19 August, on suspicion of arson. He has been bailed to a date in September pending further enquiries.
Enquiries are ongoing and detectives from Bexley CID are appealing to anyone who may have witnessed the incident to call them on 101.
Alternatively, any witnesses who wish to remain anonymous, can call Crimestoppers on 0800 555 111.