LONDON — Simon Lester logged on for his shift as an on-call paramedic for Jewish rescue service Hatzola at 7 a.m. on Monday morning. Minutes earlier, he’d heard the devastating news — that four ambulances from a neighboring branch of the Jewish volunteer group were destroyed in an arson attack in Golders Green, a northwest London suburb with a large Jewish population. “I’m speechless that people could stoop so low as to attack an ambulance that saves the lives of everybody,” Lester told The Times of Israel. The feeling among his co-workers, who donate their time and life-saving skills to...