Britain has seen terror before. The IRA’s bombing campaigns in London, Dublin and Manchester; the Islamist terror attacks of 7/7; and yesterday in Manchester, when, as Jews marked Yom Kippur, the holiest single day in the entire 354 days of…

Britain has seen terror before. The IRA’s bombing campaigns in London, Dublin and Manchester; the Islamist terror attacks of 7/7; and yesterday in Manchester, when, as Jews marked Yom Kippur, the holiest single day in the entire 354 days of…