It has reinforced fears that Moscow intends to annex "unlawfully" a vast portion of the ice-covered Arctic, beneath which scientists believe up to 10 billion tons of gas and oil could be buried. Russian ambition for control of the Arctic has provoked Canada to double to $40 million (£20.5 million) funding for work to map the Arctic seabed in support its claim over the territory.

The Russian ice breakers patrol huge areas of the frozen ocean for months on end, cutting through ice up to 8ft thick. There are thought to be eight in the region, dwarfing the British and American fleets, neither of which includes nuclear-powered ships.