Labour must reverse years of ­political failure on extremism to stop it ­fuelling more disorder, violence and terrorism in Britain, leading figures have said.

Neil Basu, the former head of counter-terrorism policing, and Dame Sara Khan, previously the government’s counter-extremism tsar, warned that proposals unveiled last month would not be enough to address a toxic pool of hatred, conspiracy theories and “dangerous rhetoric” from high-­profile figures including Elon Musk.