IT WAS a trek featuring some of the most inhospitable terrain on earth, but two men on motorbikes have finally reached their journey's end.

After spending three months travelling through Europe and Africa, Ewan McGregor and Charley Boorman concluded their 15,000-mile adventure from Scotland to South Africa, celebrating in Cape Town yesterday against the spectacular backdrop of Table mountain.

Since they began in May in John O'Groats, the intrepid duo have ridden through 18 countries, including Libya, Ethiopia, Sudan and Rwanda. Along the way they encountered blinding sandstorms, searing temperatures, dodgy border crossings and armies of ants.

But, despite the extreme riding conditions, McGregor insisted the trip, the successor to their BBC series Long Way Round, had been well worthwhile. "Long Way Down has been an amazing journey and it has been a real privilege to be able to experience these diverse and beautiful places," he said.

"We've had the opportunity to see such different ways of life to ours and have travelled to remote places very few people have access to. The sense of freedom and exploration has been incredible."

Boorman admitted the gruelling odyssey had involved some difficult moments. "There have been times when it has been unbelievably hard-going," he said. "But that has been countered by amazing riding and extraordinary people.

"Africa is a continent full of undiscovered wonder and we both feel incredibly lucky we've been able to experience this together and to have survived with some brilliant stories to tell. We were both up for an adventure and Africa has certainly given us that."

A camera crew of five and a medic accompanied McGregor and Boorman on the journey, which aimed to raise funds for Unicef, the Children's Hospice Association Scotland (CHAS) and Riders for Health.

The same BBC team also documented the pair's 2004 adventure Long Way Round, a 20,000-mile ride from London to New York via Kazakhstan, Mongolia and far eastern Russia.

The new series won't air until the autumn, but for the first time fans have been able to follow the Long Way Down event online through blogs and video clips.

On his last post, McGregor enthused: "Look where we've got to, look! We're in South Africa, we made it! We made it all the way down from John O'Groats to our last border crossing."

Earlier instalments showed the actor suffering from the severe heat of central Africa and falling off his bike in Zambia. Despite being slowed down by several searches at border crossings, there was time to visit the Pyramids, coffee plantations, landmine projects and a farm for delinquent crocodiles.

McGregor's wife, Eve, joined the bikers on the last part of the journey after meeting her husband by Lake Malawi. Boorman jokingly complained that he felt a little left out by the reunited couple.

He said: "Eve is here, with Ewan, and you know, it used to be Ewan and me, and now it's Ewan, Eve and what's that guy's name again? Oh yeah, Charley."

The team also visited a Unicef rehabilitation project in Uganda, meeting children who had been abducted to fight in civil conflict in the northern part of the country.

In one clip, showing McGregor in tears, he said: "The boys are taught to be soldiers, and to go out and kill and maim people at the age of six, seven, eight, nine you know. It's just horrendous. We came here to see the work that Unicef is doing to try to get them back into a normal everyday life."

The restless pair have promised the African adventure will not be the end of their peregrinations. Boorman said a trek from Alaska to South America could be next.