Police calm London, but riots flare across UK

LONDON — Thou­sands more police offi­cers flooded Lon­don streets Tues­day in a bid to end Britain’s worst riot­ing in a gen­er­a­tion as ner­vous shop­keep­ers closed early and some res­i­dents stood guard to pro­tect their neigh­bor­hoods. An eerie calm pre­vailed in the city, but unrest spread across cen­tral and north­ern Eng­land on a fourth night of vio­lence dri­ven by poor, diverse and brazen crowds of young people.