A report into conditions at Brixton Prison found that inmates were smoking so much cannabis that even the inspectors' clothes started smelling of it.
The report also concluded that the availability of illegal drugs was fueling much of the bullying at the prison.
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Pictures of today's events unfolding following a major security incident at the Houses of Parliament.
At least two people have died after a knifeman brought terror to the heart of Westminster.
The Cobra committee brings together government ministers with senior officials of the emergency services and security agencies.