Russia’s leader has told “unfriendly” nations they must start paying for gas in roubles from April 1, 2022, or Moscow will cut off their supplies. President Vladimir Putin signed a decree the previous day stating that foreign buyers “must open rouble accounts in Russian banks". The decision is seen as an attempt to boost Russia’s currency, which has been hit by Western sanctions as a punishment for Moscow’s decision to invade Ukraine. As the supplier of about 40 per cent of the gas used in the…