Tony Sewell is certain he knows why black British boys are stabbing one another in the streets, yet — despite his background and expertise — politicians will not listen to him. “People who have got the levers of power don’t want to hear me,” says Sewell, an educationalist and member of the Policy Exchange think tank. “Everyone wants me to say it’s all about victimhood and being under the cosh of oppression. People are almost like, ‘OK, you don’t have to blame all white people — say it’s just two white people. Then the deal would be done!’

“If I came out with, ‘Three hundred years of slavery is the reason’, then maybe I’d be making a truckload of money. But I refuse to accept