How do you earn money as an adventurer?

Primarily from books and talks, which started as soon as I married my late wife, Ginny, in 1970. I had to leave the Army and we decided to make a living from doing expeditions and gaining income from talks. I would lecture for £18 in town halls all over London to audiences that were often made up of a dozen old ladies.

Even today, talks are by far my most profitable way of making money because with books my agent takes 20pc and the government takes 40pc tax. That's why I have never hired a ghost writer – there'd be nothing left for me. My sponsors never pay a single penny directly to me – all the expedition money goes direct to the suppliers.

I work out what it will cost to fund a trip and which charity will benefit. I have letters stating our expeditions have raised £12.8m for British charities to date and I'm hoping it will soon become £15m.

Did you notice a time when you suddenly started earning more from lectures?

Yes. In the 1970s big agencies like Foyles started telling me that I was no longer in the correct price bracket for working men's clubs, schools and Women's Institutes. That's when I started lecturing at commercial conferences and sales rewards events.

Has the credit crunch had an effect on you?

Not yet, but at the back of my mind I'm quite worried my bookings may start to dry up. There's a lot of competition on the speakers circuit. I've got lots of bookings at the moment, but I wouldn't read too much into that because they were mostly booked before the current banking crisis.

How did your childhood influence your attitude to money?

My childhood was in South Africa in Constantia where my ancestors had started vineyards. I was never given any pocket money until I was sent to Eton College in England at the age of 12, when I was given £4 a term. When I left five years later I was still on £4 even though things had become more expensive. The key to life at Eton was buying food at the tuck shop. If your £4 wouldn't stretch to the end of term you would go up to other boys and ask them to lend to you. I was usually told, 'Shove off and beg elsewhere,' so I learned to nurse and shepherd every penny of that £4. I'm still very cautious with money now.
 

To read the full interview please visit The Telegraph