Police officers who were on duty in Notting Hill during one of the most infamous race riots in British history bear witness to a very deep level of racism which went completely unchecked at the time.
What caused those weeks of violence and how did the authorities cope? Initially, not very well.
Six months after the riots Kelso Cochrane, a young West Indian, was stabbed to death and his murderers never found.
Enoch Powell's infamous 'rivers of blood' speech brought dockers and meat workers out on strike in his support.
The government, though aghast in public, in private began to make plans to limit immigration.
And in so doing, they inadvertently laid the foundations of Britain's race relations policy today.