It seems that the roots of the Notting Hill Carnival are in dispute since both Claudia Jones and Rhaune Laslett-O'Brien have a claim to be the originator. Claudia organised the first indoor event at St Pancras Town Hall in January 1959 and organised a similar event every year until her death in 1964. Rhaume organised the first outdoor event in August 1966.
We don’t want to enter this murky territory, well-flagged as troublesome at the Rhaune Laslett-O'Brien website: “Ask anyone involved who owns carnival and they will say the same thing: the people. The trouble is, which people? Since Rhaune Laslett handed over responsibility for the carnival, the primary body organising the event has split, reinvented itself, then split again several times. It has been called the Carnival Development Committee, the Carnival Arts Committee, the Carnival Enterprise Committee and, at present, the Notting Hill Carnival Trust, which is itself riven by internal rows. Each group has its own version of the carnival's history and development.”
And then Russell Henderson was also an early initiator and Leslie Palmer had a major influence later on.