“There was a flash and a loud bang. The vehicle rocked. I thought ‘f***, we have hit a mine. I checked the rest of the crew were OK. Luckily they were. But we had no communications. That was tense. The risk of another Taliban attack was high. But all of a sudden we had two Apache helicopters over us, protecting us. I have never seen a more blessed sight.”

Paul Nelson (not his real name) is a Lieutenant in the Household Cavalry division of the British Army. The same regiment you see on regimental duty outside Horse Guard’s Parade in London.

Nelson is lucky. A direct hit by a roadside bomb or mine often ends in injury or indeed death, but he and his unit escaped unscathed and left Afghanistan without a single casualty. Among those who safely returned was their most celebrated member: Lieutenant Harry Wales. Otherwise known as Prince Harry.

“Having him with us in Afghanistan was a good omen,” says Nelson, who joined the army at almost the same time as Harry. “Everyone came back OK. That’s unusual.”

It’s a few weeks since Nelson’s life hung in the explosive balance in Afghanistan. Now he is in another vehicle, a Land Rover, on another continent, Africa. In the morning, Prince Harry is joining Nelson, their commanding officer Major Tom Archer-Burton (the only man capable of telling Lt. Wales to do press ups for as long as he feels necessary) and 24 other men on a charity expedition through southern Africa.

The Burnaby Blue expedition was Archer-Burton’s brainchild, but when his royal charge heard of the plan for an adventure through Mozambique, South Africa, Zambia, Malawi, Namibia and Botswana, Prince Harry suggested adding Lesotho to the itinerary and raising money for his Sentebale HIV/AIDS trust. ‘Archie’ agreed and allowed Harry to join the trip from Botswana, through Namibia and South Africa to Lesotho.

“It would have been impossible to have had him in Mozambique and Zambia,” the Major told me when I became the only journalist allowed to join the expedition. “We had to keep the expedition quiet whilst in Zambia and Mozambique. Really until we got into Botswana. In effect we were circling Zimbabwe at the time of the elections and that could have been misconstrued. Luckily the Land Rovers we are using do not look threatening.”

I joined the expedition at the crossroads of Africa, the point in northern Botswana where four countries come together and the frontier with a fifth, Angola, is only 50 miles away.

Archie is the man who pushed for Harry to fight in Afghanistan. He had been due to go to Iraq but families and the press said he would have been too much of a ‘bomb magnet’. So to send him to Afghanistan without anyone knowing was the only way.

“He was desperate to join his men,” Archie tells me. The two are close friends and there is an air of excitement among the men as the day of his arrival approaches, not because of his celebrity, but rather because he is a mate and they are looking forward to seeing him. Being royal affords no special treatment.

Harry’s comrades are a good bunch. In Afghanistan they would have died for him and for one other. In Africa the fear that characterises war is, thankfully, absent, yet the blood-brotherly bond forged in Afghanistan is still evident.

Outside Maun, we spend the night downing white African brandy called Klipdrift and Coke toasting a South African Household Cavalry officer who died in action.

The next day, unexpectedly hangover free, I am required to leave the expedition for a few days. I rejoin the boys in Lesotho, where they are spending three weeks rebuilding a home for disabled children in an area afflicted badly with HIV/AIDS.

After weeks of travelling with his comrades, it is in Lesotho that I finally get to meet Harry.

Taller and more brawny than he appears in photographs, he is also more normal than a royal upbringing should have allowed. There is no bow required, nor am I expected to address him ‘Your Highness’. In Africa he is simply Harry.

“It’s good to be with the boys, and not being shot at,” grins Harry. “And it’s great to have the boys with me in Africa. Bringing them [to Lesotho] has contributed 360 days of work to the project here… rebuilding the only handicapped school in Africa. Look, the guys have been digging a trench. Already they are two metres down. That’s what happens when you have got army guys.”

As the royal press pack follow his every move, I sneak off to chat to Harry’s comrades. They mean everything to him but not to the paparazzi. They don’t mind. The effect Harry has had on the regiment is immense. Recruiting is riding high and respect for the army, low in the UK compared with other NATO allies, is finally on a rise, which they attribute in part to his efforts.

“We paraded through Windsor on our return from Afghanistan,” recounts Captain Jason Biswas, who served in the same bunker as Harry. “And the crowds flocked out. OK, Harry was there but they were shouting ‘well done boys…and calling us heroes’. If that’s down to the Harry factor then that’s fine. Because it gave us immense pride.”