Fiona Thornewill has already walked to both poles with her husband Mike

Rosie Stancer, a 43-year-old cousin of the Queen from London, and Fiona Thornewill, 37, from Nottinghamshire, are leaving Britain on Wednesday on the same flight.

But both insist they will not race as they tackle the freezing and windswept climate for 700 miles.

"In some small way it is almost reassuring to know there is another woman out there on her own," said Ms Stancer, who is a freelance writer.

Heavy sleds

"I know people want to make it into a race but the challenge for me is huge enough - it is dangerous to talk of a race," said Stancer.

Ms Thornewill, from Thurgarton, echoed her sentiments: "There is no racing involved whatsoever, I just take my hat off to her."

The recruitment consultant, who has been pulling tyres, cycling and lifting weights, said they had exchanged e-mails and were planning to meet before the challenge.

The ambient temperature will be -25 degrees C but with the wind chill factor it will go down to -50 C Fiona Thornewill Polar explorer

Ms Stancer admitted she was "startled" when she found out there was another woman undertaking the same challenge.

"I was thinking I had the whole of the Antarctic to myself but it is everyone's right to be there.

Both women will pull sledges weighing about 120kg - double or more than double their body weight.

Ms Stancer expects the �150,000 trip will take 65 days - Thornewill has allowed five days more for her �100,000 expedition.

Only one woman has ever previously succeeded in the walk - Norwegian Liv Arneson in 1994.

Snow diet

Ms Thornewill is hoping to meet her husband Mike - who is taking six novices on a shorter route - at the pole in mid-February.

Chocolate bars, nuts, six litres of water and dehydrated meals in the evening feature in their diets, with snow being used to reconstitute their main meal.

The pair leave Britain on Wednesday and fly to Punta Arenas in Chile.

Both women have completed the trip before - but never alone.

Ms Thornewill is also under no illusions about the expedition: "The ambient temperature will be -25 C but with the wind chill factor it will go down to -50 C.