UK Labour leader Keir Starmer is a former human rights lawyer turned-state prosecutor whose ruthless ambition and formidable work ethic look set to propel him to Britain’s highest political office. The 61-year-old, whose unusual first name was his socialist parents’ tribute to Labour’s founding father Keir Hardie, is also the centre-left party’s most working-class leader in decades. “My dad was a toolmaker, my mum was a nurse,” Starmer tells voters often, countering depictions by opponents that the one-time “lefty lawyer” is the epitome of a smug, liberal, London elite. With his grey quiff and black-rimmed glasses, Starmer remains an enigma...