The UK assets of Alisher Usmanov, left, and Igor Shuvalov have been frozen in the latest tranche of British government sanctions. Getty Images/AFP
The UK assets of Alisher Usmanov, left, and Igor Shuvalov have been frozen in the latest tranche of British government sanctions. Getty Images/AFP

Who are Alisher Usmanov and Igor Shuvalov, the $19bn oligarchs hit by UK sanctions?