Coming to the Polar Star 's support, the 36,000hp Russian icebreaker Krasin left Vladivostok for the Antarctic on 21 December 2004 to smash a passage through the 3.5m thick ice to the McMurdo mooring. The joint operation went smoothly until early last month when a 160km iceberg in the shape of Long Island hit the Antarctic coast.

It rammed the mainland so hard that earthquake seismographs registered the impact. It then split into five huge chunks, blocking the exit from the bay where the polar explorers were based.

While the Krasin and Polar Star looked for passage across the immense island of ice the weather deteriorated sharply and the Krasin had to break ice continuously around the US freighters to stop them from becoming trapped. Eventually, all the relief ships successfully reached their moorings.

Brian Stone, a spokesman for the US National Science Foundation, sent a telegram to Viktor Kovalchuk, the Krasin 's captain, praising him and his Russian crew for their professionalism, rapid response and bravery. He said the complexity and speed of the Russian relief operation meant that Russian sailors would always be welcome at McMurdo.

Yevgeny Ambrosov, the general director of the Far Eastern Sea Navigation said, 'If our icebreaker had failed, about 1,000 people would have had to have been evacuated, and the US research and observation programme that has been underway in the Antarctic for many years would have been disrupted.'

The Krasin is currently making its way back to Vladivostok and will arrive early next month.

MJ Information No: 20401