There is a pattern to how certain crimes become political weapons in the UK. It begins with a real horror. It ends, reliably, somewhere that has very little to do with the dead. Henry Nowak was 18, a first-year student in Southampton, walking home from a night out when Vikrum Digwa stabbed him five times. The footage of what came next — Nowak handcuffed on the pavement, bleeding, telling police officers he had been stabbed, telling them he couldn't breathe, his pleas being dismissed — is harrowing.