A police officer is heading for the North Pole to raise money for a children's cancer charity.

Pc Darren Ariss, aged 35, will be competing in the Polar Challenge, one of the toughest and most extreme endurance challenges on Earth.

Mr Ariss and his team-mate Tommy Dalman, aged 27, a Birmingham-based businessman, set off from Resolute Bay, in Canada, on Wednesday.

After a 60-mile trek just to get to the start line, the pair will race on skis, pulling 100lb sledges, to the Magnetic North Pole.

The race covers a distance of 350 nautical miles through one of the most hostile environments in the world. It is due to finish around May 10.

Temperatures can drop as low as -35?C and the team will have to guard against the dangers of frostbite, hypothermia and polar bears.

Pc Ariss, of Claverdon, Warwickshire, who is a tactical trainer based at Bromsgrove Police Station, said: "This is a once in a life-time opportunity that will push the competitors to the absolute limit both mentally and physically."

"To put this into perspective, more people have climbed Mount Everest than have travelled to either of the Poles," he added.

Money raised by the expedition will go to the Society of Parents of Children with Cancer, which is based at the cancer ward at Birmingham Children's Hospital.

Both Pc Ariss and Mr Dalman play rugby for Claverdon Lions. They chose SPOCC because the daughter of a team-mate is being treated at the hospital.

Pc Ariss said: "Birmingham Children's Hospital treats seriously ill youngsters from across the Midlands, providing an essential service to the local community. Anyone who spends any time on the ward will realise what a worthy cause this is."

He added: "I myself have a five-year-old daughter, Beth-any, and as a parent I can appreciate what vital work a specialist children's hospital does."

Anyone wishing to sponsor the Polar Challenge team or give a donation should visit the Claverdon Rugby Club website at www.clavrfc.co.uk.