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.
More top news
The plaque at number 16 Cowley Street in Westminster marks the brown brick Georgian townhouse where Sir John lived for 31 years.
A man reportedly armed with several knives has been arrested in Whitehall on suspicion of planning a terror attack, police have said.
Metropolitan Police officer, Tom Harrison, has been crawling the course since the race began on Sunday morning.