An inmate at HMP Belmarsh in Greenwich has died after he was taken to hospital in a critical condition suffering from head injuries.
The 36-year-old man was found by officers at around 8pm on Tuesday but later died on Wednesday evening.
Two men, both aged 28, who are also inmates at the prison, were arrested at the scene on suspicion of attempted murder. They have been remanded in custody.
Detective Chief Inspector Richard Leonard: “We are working to establish the circumstances surrounding this incident with the support of SERCO and local officers.
“At this stage I am open minded concerning motive, but expect this to become clear as the investigation progresses.”