It was dark and I was heading home from the gym: past the Salvation Army church, past the housing advice office, past the bus stop and Tesco Express, past William Hill, past the dead phone kiosks and the seemingly eternal builders' fencing hiving off where Don's Cafe used to be. And then this man sprinted past me, crop-haired, small, bearing a little rucksack. I didn't see his face. I recognised his run, though. It was the frantic, panicky sprint of man fleeing trouble and my first thought, of course, was "knife crime." Someone was going to catch him and stab him, and the question was how soon and how close to right under my nose.