Julian Assange is being held in Belmarsh Prison, termed the "English Guantanamo."
According to Wikipedia:
"Between 2001 and 2002, Belmarsh Prison was used to detain a number of people indefinitely without charge or trial under the provisions of the Part 4 of the Anti-terrorism, Crime and Security Act 2001, leading it to be called the "British version of Guantanamo Bay". The law lords later ruled in A v Secretary of State for the Home Dept that such imprisonment was discriminatory and against the Human Rights Act.
...In May 2007, there was a violent disturbance in the prison, Sky News reported. At least four prison officers were injured.
...In November 2009, an inspection report from Her Majesty's Chief Inspector of Prisons criticised the "extremely high" amount of force used to control inmates at the prison. The report also stated that an unusually high number of prisoners had reported being intimidated or victimised by staff at Belmarsh."
Note: there are protests for Julian at the prison today and tomorrow, details in this graphic: