The UK on Monday hit Russia’s central bank with new sanctions and relaxed visa rules for Ukrainians fleeing the invasion, but dismissed President Vladimir Putin’s nuclear readiness alert as sabre-rattling. In his latest call with Ukraine’s leader Volodymyr Zelensky on Sunday evening, Prime Minister Boris Johnson praised the “heroic” resistance of Ukrainians, according to Downing Street. Johnson released a further £40 million ($54 million, 48 million euros) in humanitarian aid for Ukraine, after he gave an emotional address to worshippers at London’s Ukrainian Catholic cathedral. “Never in all …