A murder enquiry has been launched following the death of a man in Wandsworth Prison.
Police were called at 07:35hrs on Monday, 4 May, to reports of a male prisoner deceased in a cell.
The deceased is believed to be aged in his 60s.
Next of kin have been informed. Formal identification has not taken place.
A post-mortem examination will take place in due course.
A man in his 40s, also a prisoner, has been arrested on suspicion of murder. He is currently in police custody.
The murder investigation is being led by Detective Chief Inspector Rebecca Reeves of the Homicide and Major Crime Command. Enquiries continue.