The team of three, led by record breaking polar explorer Pen Hadow, will be measuring the thickness of the ice to give scientists a better idea of just how long the ice cap could survive.

They will travel 746 miles towards the Pole in three months, braving temperatures as low as minus 55 degrees, hauling sledges containing a radar unit to measure the ice.

Mr Hadow, 46, and the other members of the Catlin Arctic Survey group, Bradford woman Ann Daniels, 44, and Martin Hartley, 40, flew out from Heathrow airport to Canada from where they are due to set off on the expedition from the north of the country on February 27. They expect to reach the North Pole in late May.

They hope the new data, which will differentiate between the snow and ice, will give a better picture than measurements from satellites and submarines.

Climate change means that the ice cap has dwindled to the point where a large section disappears entirely each summer and some fear the loss could become permanent within four years.

Mr Hadow, a father-of-two from Hexworthy, Devon, became the first person to trek solo and without support from Canada to the Geographic North Pole in 2003.

He said this expedition will reconnect exploration "with its roots in science and discovery".

As he prepared to fly out from Heathrow, he said: "I've seen how the ice is deteriorating fast and we could lose this amazing, huge white feature at the top of the world alarmingly soon. If we can help scientists understand what is going on, then we'll have done something positive. We'll have done our job."

Both Mr Hadow and expedition photographer Mr Hartley, from Hackney, east London, will celebrate their birthdays while on the ice.

People can track their progress via the expedition's website www.catlinarcticsurvey.com.

Ms Daniels, a mother-of-four from Whimple, Devon, said: "It will take it to people in their armchair. It makes it real and people can follow us every step of the way."