Denmark might be given the task of inspecting and potentially blocking tankers of Russian oil sailing through its waters under new EU plans, as western powers scramble to enforce a price cap the Kremlin has learned to avoid.

Denmark would target tankers transiting the Danish straits without western insurance, under laws permitting states to check vessels they fear pose environmental threats.

All of Russia’s oil shipped through the Baltic Sea, roughly 60 per cent of its total seaborne oil exports, crosses the narrow Danish straits on its way to international markets.