Two nuclear submarines – one British and one American – have met up at the North Pole after conducting exercises beneath the Arctic ice cap.

Trafalgar-class hunter-killer HMS Tireless was joined at the top of the world by Los Angeles-class boat USS Hampton in the early hours of yesterday morning when both vessels forced their way through the ice at the Pole.

Nuclear-powered submarines are the only type of boat capable of sustained deployments to the icy extremes of the planet, and this visit marks the first by a Royal Navy vessel for eight years.

The Royal Navy is keen to maintain its expertise of under-ice operations, and this series of exercises has sharpened that knowledge while demonstrating the reach and capability of the British submarine fleet.

Tireless has taken part in a series of equipment trials and tactical development during the exercises with the Virginia-based American submarine.

The trip north also offered scientists the opportunity to undertake research on the ice cap, with civilians joining the crew of both submarines.

Such opportunities are highly-valued by the scientific community, as the thickness and quality of the polar ice can be measured with a great deal of accuracy from underwater.

Such measurements are of significant value now as global warming appears to be causing the retreat of the permanent pack ice – up to 100 miles in recent years – and thinning in the summer to as little as six feet.

Measurements from below the ice are only possible at the North Pole as the Arctic ice cap sits on the sea, unlike the Antarctic, which is a land mass.

Apart from the novel experience of surfacing into a white world where the springtime air temperature is minus 22 degrees Centigrade – and with the threat of prowling polar bears in the vicinity – the two crews are expected to get some welcome exercise playing a game of football.

And the Americans should be warned – the Tireless crew recently beat their French hosts during a visit to Brest by eight goals to nil.