In a statement, Ofcom said: "We carefully considered a large number of complaints about this artistic routine, an area where freedom of expression is particularity important."
"Diversity's performance referred to challenging and potentially controversial subjects, and in our view, its central message was a call for social cohesion and unity."
"Any depictions of violence by the performers were highly stylised and symbolic of recent global events, and there was no explicit reference to any particular political organisation - but rather a message that the lives of black people matter."
"We will not be taking this case on to formal investigation."