I first had money for investment just at the time of the 2008 crisis and shares have been highly volatile since then. So I do have shares in my pension but I have tended to invest in specific projects that include property and private companies that have been very well researched by my advisers.

I've been asked a lot lately if tennis is clean or not. I don't know any more how you judge whether a sport is clean. If one in 100 players is doping, in my eyes that isn't a clean sport.

I'd like to say that I am romantic person, but I don't think I am. When I won my first tournament I went into the crowd and kissed my girlfriend. I was 18 and didn't have my coach with me, I was there on my own, and I just needed to celebrate with someone I knew. I always start out with good intentions. I'll say something nice, then I'll just put my foot in it and ruin the moment.

Let it be your business every day, in the secrecy of the inner chamber, to meet the holy God. You will be repaid for the trouble it may cost you. The reward will be sure and rich.

I'm a global ambassador for the World Wildlife Fund and United for Wildlife and I am also a Unicef UK ambassador. It's important to me to support charities. I never want to take my wealth for granted.

Owning a property is great as that's my base and the centre of my family life.

Since there are a wide range of entrepreneurs fundraising at any given time, I looked at each opportunity as it has arisen and on its own merits. Then I've sat down with my financial advisers, we've looked at the numbers and gone for the businesses I believe have real potential.