Rob Gauntlett and James Hooper sail into Sydney Harbour

Two young British explorers have sailed into Sydney Harbour as part of a natural-powered adventure aimed at raising awareness on green issues.

Rob Gauntlett and James Hooper completed a trip from the North Pole to the South Pole in April and immediately set sail for Australia.

They arrived on Friday, right on schedule, after travelling 1,800 nautical miles and spending 70 days at sea.

Mr Hooper said they were looking forward to celebrating their 21st birthday "in the warmth of Sydney".

The pair, both from Sussex, aimed to raise awareness about climate change by using only human and natural power for the trip.

They said they wanted to prove to their generation that you can achieve the "impossible".

During their gruelling expedition from Pole to Pole, the duo skied, dog-sled, sailed and cycled through Greenland, USA, Mexico, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Ecuador, Peru, Chile, and Argentina.

While skiing and pulling their supplies between Canada and Greenland, Mr Gauntlett fell through the melting sea ice and was left unconscious for three hours as Mr Hooper phoned for help to organise their evacuation to safety.

Determined to continue, the pair - both former pupils of Christ's Hospital in Horsham - then sailed to New York to begin the 11,000-mile cycle ride to Punta Arenas, Chile. Their expedition is helping to raise money for the Prince's Trust.

The pair became the youngest Britons to climb to the summit of Mount Everest aged just 19 on May 17 2006.