Oligarchs Alisher Usmanov and Igor Shuvalov – worth a combined $19bn – sanctioned with immediate effect.Putin associates now cut off from their significant UK interests including mansions worth tens of millions.Pair’s assets frozen, both are hit with travel bans and no British citizen or business can deal with them.Oligarch Taskforce to target Russian elite expected to be launched next weekToday the Government has announced that a full asset freeze and travel ban has been imposed against Alisher Usmanov and Igor Shuvalov, two of Russia’s leading oligarchs with significant interests in the UK a…