George Paul witnessed the arrest of one of the suspects in Westborne Grove and told ITV News he saw "three policemen holding down one individual - I don't know what ethnic origin he was but he was shouting.
"It was all over in ten minutes."
More top news
Family holidays to Europe could rise by an average of £230 if Britain leaves the EU, the prime minister is warning.
The social network faced fury after it barred a feminist group's image for an event promoting body diversity and acceptance.
Barack Obama left the owner of a streetside restaurant in Vietnam "stunned" when he stopped off there for a $6 meal.