Online platforms told they risk stirring up hate and violence

Ofcom has told social media firms - which have been blamed for stoking the unrest sweeping parts of the UK - that there is "no need to wait" to make their platforms safer.In an open letter, the media regulator said there was an "increased risk" of the sites being used to "stir up hatred" and "provoke violence".Ofcom is due to get tougher powers under the Online Safety Act, which has become law, but has not yet…