by Martin Jefferies

Intrepid explorers Paul and Helen Crittenden have bade farewell to Ramsgate as they set off on a remarkable worldwide adventure.

The couple plan to circumnavigate the globe by travelling 66,000 miles across 45 countries, 21 mountain ranges and seven deserts, all behind the wheel of an ageing Land Rover Defender.

Every inch of 16-year-old "Landy", which was bought on eBay for just £6,500 but has since undergone some major modifications, was crammed with supplies at the Crittendens set sail on an LD Lines ferry bound for Ostend.

It will take up to 18 months to complete the epic expedition, during which Paul and Helen will drive across eastern Europe and Asia before catching a boat from Russia to Alaska and embarking on the long trek through Canada and the United States. From there, they will drive down through the central and southern Americas before heading across the South Atlantic Ocean to South Africa, journeying through the barren deserts of Africa and rejoining the more predictable roads of western Europe.

Every mile of the Paul and Helen's unconventional challenge will be tracked on an educational website, allowing children to embark on their own 'virtual field trip'. School pupils will be able to read about the couple's adventures, look at photographs and videos from across the world and talk to the pair as they continue on their travels.

Paul and Helen hope their round-the-world trip will raise more than £6,000 for Water Aid, the Christina Noble Children's Foundation and Rainforest Concern.

For more information about the expedition, visit www.goingoverland.com or the educational website, www.landysadventures.com.