LONDON (Reuters) – British Prime Minister Boris Johnson said Britain and its allies had taken “decisive action” on Saturday to shut Russia out of the global financial system by cutting its banks’ access to the SWIFT international payment system. “We have taken decisive action tonight with our international partners to shut Russia out of the global financial system, including the important first step of ejecting Russian banks from SWIFT,” Johnson said on Twitter. “We will keep working together to ensure Putin pays the price for his aggression.” (Reporting by Michael Holden; Editing by Cynthia O…