In 1999 at the age of 26, Richard Reed quit his job in advertising to set up smoothie and juice company Innocent Drinks with fellow Cambridge graduates Adam Balon and Jon Wright. In 2009 Coca-Cola bought an 18% stake in the company; by 2013 it owned over 90%. Reed, Balon and Wright set up venture capital fund JamJar Investments, which backs businesses such as Graze and Deliveroo. In October 2015 Reed was named deputy chairman of the Britain Stronger in Europe advocacy group.

You’ve asked 62 remarkable people to pass on advice for your new book, If I Could Tell You Just One Thing. What have you learned about success?
Blimey. OK, if you took a representative sample, what things were disproportionately prevalent? Dyslexia, definitely: so Jo Malone, Heston Blumenthal, this crazy super-agent guy Ari Emanuel, Richard Branson. At school they had an irregular approach to academic learning and they were ostracised. Jo Malone sees it as a gift. She went into a school recently and asked anyone to stand up who’d got dyslexia and she said to all the other kids: “Look at these people and thank them. They are extraordinary, because they’ve got creative skills and you are going to learn loads from them.” That’s a great way of thinking about it.

It’s a broad church of people you speak to: from Bill Clinton to Marina Abramović to Simon Cowell. Is there something that unites them?
The most common thing is that everyone keeps sharpening their sword, whatever it is they do. Mick Jagger still spends time with this amazing Brazilian choreographer to learn cool new dance steps. Edna O’Brien, the novelist, makes herself read and reread great literature every single day, because she’s says it’s like a boxer, she wants to keep fit and keep training. It’s the most cliched thing to say, but no one’s doing it through divine gift, everyone’s doing it through repetition, honing, training. Working more, harder, better, deeper, faster. Keeping going.

You’re the co-founder of Innocent Drinks. Have you found a correlation between success and happiness?
I was extremely lucky because I went into business with my two closest mates. We were committed to being a group of friends and then we tried to find out something we could do as a group of friends. That’s when we got into smoothies. But did we set it up with the view to create happiness? The truth is, yes we did. We had a zero-cock policy: don’t employ any cocks, don’t put up with any cocks. The vibe of the business to this day is that it’s full of altruistic, ambitious people, so it’s just an encouraging place to be.

Is it true you were personally responsible for “wackaging” – the quirky labels that are now everywhere?
Yes, that was part of my beat. I do think, oh my God, will my long-term contribution to the species be that I was the guy who introduced really annoying body copy on packaging?

Was it an Innocent innovation?
If we can make one claim, we can make this – that was new. I’ll tell you where it came from: have you seen Kingpin?

The tenpin bowling movie with Woody Harrelson? Of course.
Well, there’s one scene, it’s not an integral scene, where somebody goes round to somebody else’s house and says: “Oh, I’m desperate for a dump, have you got anything to read on the toilet?” The guy looks around and passes him a bottle of shampoo and he looks at it and goes: “No, I’ve read this one already.” That’s where the idea came from.

You sold your shares in Innocent to Coca-Cola in 2013, becoming very rich in the process. Does that change your approach to work?
Bear in mind, I started out on £2 an hour in a dog-biscuit factory in Huddersfield, and bear in mind, my dad was a bus conductor and my mum was a nurse. I’m in a position now which I’d never have dreamed of. So I’m massively grateful for it. Has it changed my approach to work? Well, it’s changed the work that I do, in that now I can invest a morning a week writing film scripts that quite frankly are probably never going to get bought. I can write this book and 100% of the money is going to charity. I’ve now doubled down the time, energy and money I spend on the philanthropy stuff I do and helping young entrepreneurs set their first businesses up with our new company JamJar. I can do that because each month I have an amount of money paid into my bank account and that’s more than I need to pay for the stuff I want to buy that month.

You were deputy chair of Britain Stronger in Europe during the referendum. A few months on, has the pain lessened?
Well, it had until the Conservative party conference. When Theresa May became prime minister, I thought, thank God for that. Not one of these loony men who are chasing around their own egos and repressed whatevers. But then at the conference she stood up and basically pitched herself to the Daily Mail. I just thought, I don’t understand! Why don’t you want to be this brilliant unifier? Why are we demonising people just because they weren’t born here? Fish and chips, Marks & Spencer, the Mini: three of the top five things people say Great Britain is about – all made by immigrants. I’ve been travelling around Europe for the past month and we look like Racist Island.

You’re a keen climber. Is there a particular peak you’ve set your sights on?
This started at a friend’s 40th birthday four years ago and the first one was Mont Blanc. So we go off and do it, a few of us, and the next year I say to the guys, “What are we going to do next?” And they’re like, “We’re not allowed to do any more, the wife’s said so.” So I went and climbed the Matterhorn with a friend of mine. Then I decide to do the Eiger. At this point I’ve gone from doing it with five friends, to one friend, to no one. It’s just me and a guide. And there’s bits where I’m having to step from one rock to another rock and there’s a kilometre drop, and I just thought to myself, I need to get a new hobby. So I got to the top, came down and I started guitar lessons.

Finally, you’ve asked everyone else for advice, what’s the one piece of wisdom you’d pass on?
Contribute. Whatever situation you are in. So if you’re round your friend’s house, contribute to washing up after you’ve had the dinner. In the workplace, your career is only going to be enhanced by you offering to contribute more. If you come across a charity, contribute. And if you don’t have money, contribute time. And if you don’t have time, contribute clothing. One of my favourite phrases is: “If we all want a great future, we are going to have to share it.” And I think that’s more true than ever before.

If I Could Tell You Just One Thing (Canongate £14.99) is out on 3 November. Click here to order a copy for £12.29