European Union member states can now block the sale of tankers for use in Russia if they have “reasonable grounds” to believe they will be used to haul oil in breach of the bloc’s sanctions regime targeting Kremlin finances, according to new EU guidance.

New measures, which came into full force last week, are an attempt two years on from the start of the war to stifle the flow of elderly tankers from established European owners to the fleet hauling Russian oil.