Three British polar explorers have ended their sojourn on High Arctic sea ice after 73 days of hard travel and skin-freezing temperatures.

The trio had been collecting data that will give scientists a rare first-hand look at the ice's declining thickness.

"We know that that has made the expedition worthwhile," said Pen Hadow in a webcast from the ice as he was being picked up Wednesday.

Hadow and two fellow explorers were set down on the frozen Arctic Ocean on Feb. 28 about 400 kilometres west of Axel Heiberg Island, just outside Canadian territorial waters.

The team travelled on foot and by ski, pulling supply-laden sleds behind them. Although they were 490 kilometres short of reaching their goal of the North Pole, they managed to travel 440 kilometres across the ice, taking hundreds of measurements on snow and ice thickness in a region that may never have been measured before.

The expedition was sponsored by groups including the World Wildlife Fund. The route was chosen specifically to take them across areas of multi-year ice, which historically averages between two and three metres thick.

After taking 1,500 readings hand-drilled through the ice, the team found an average thickness of only 1.77 metres.

"The data [Hadow] is collecting will be very valuable," said Canadian scientist John Falkingham of the International Ice Charting Working Group. "There are very, very few measurements of ice thickness in the Arctic Ocean."

That data will be correlated with computer model predictions and other readings to fine tune theories on what's happening to the shrinking Arctic ice pack.

On the face of it, Falkingham said Hadow's readings appear to confirm that multi-year ice is growing thinner.

"It is confirming those other studies that were done by modelling," he said.

Hadow and his team were looking forward to hot showers and clean sheets in Resolute after more than two months in some of the most inhospitable terrain on the globe.

On the start of their trip, they were confronted with -30 C temperatures, with wind chills that drove the mercury down to -70 C. It was so cold, said Hadow, that equipment such as the team's ice-penetrating radar simply refused to work.

The team covered about five kilometres a day, spending nights huddled in their tent, listening to the groan and creak of the shifting ice plates. All three explorers are returning in good shape, with the exception of one team member's frost-bitten big toe.

Asked for his reaction to climbing into a plane to fly back to civilization, Hadow had one word:

"Relief," he said.