How I started
I was always quite good at maths, though from the age of about ten it was puzzles in particular that appealed to me. Then, when I was about 16, I discovered that the Sunday Times had a weekly brainteaser column. After several weeks grappling with some fiendishly tough puzzles, an idea occurred to me one afternoon for a puzzle of my own, based on a pattern of numbers I spotted on the cricket scoreboard during an England Test match. With all the optimism of youth I submitted it to The Sunday Times, and to my utter amazement they agreed to publish it. The bad news was that the lead time for publication was over six months, a long time for a teenager.
Then I discovered New Scientist's weekly Enigma column. With The Sunday Times now on my CV, I submitted a puzzle to New Scientist, and not only did they agree to publish within weeks but they wanted me to become a monthly contributor. Having to write puzzles to a deadline, at the tender age of 17, forced me to immerse myself in the world of recreational maths. I discovered the inspirational monthly column by Martin Gardner in Scientific American, which was to have a huge impact on my understanding of what maths really is. Meanwhile I was also discovering something about journalism, editing and also - most soberingly - what the public thinks of you when a mistake makes it into print.
Realising that it was the applied side of maths that particularly appealed to me, I read engineering at Cambridge, a very mathematical course. I specialised in Operational Research which I describe to people as applied puzzle solving. I then spent a few years as a management consultant, using mathematical modelling for a huge range of projects. These included working out the best places to locate post offices around the UK, and checking that Daily Mail "Bingo" games were mathematically robust.
Then maths went on the back burner for a while. Fast forward to 1997, when a friend of mine, Jeremy Wyndham, took me aside at a party and asked if I fancied writing a book with him about the sort of maths we used to talk about in the pub: coincidences, traffic jams and so on. That book was to become "Why do buses come in threes?". Published in 1998, it rapidly became a bestseller, topping the Science Museum chart for five years. We had written it for adults but soon discovered it was also being read by older teenagers.