I did not set out to be a woman in a man's world, but it has turned out that way. I went to a boys' school from the age of five to the age of 12 - very formative years - and I went to a male college at Oxford to read law. It was Balliol's first year of allowing girls in. It never fazed me being surrounded by boys from an early age. Maybe it has helped me in the City; whenever I go to meetings I am generally the only woman.
Of my four schools, I liked my prep school, Kingsmead in Hoylake on the Wirral, best. It was a boys' prep school. There was none of this feeling that girls should be treated differently; it was all very straightforward. We played cricket and football; the only thing the girls didn't play was rugby.
I was the centre of attention at Kingsmead - there were 500 boys and about four girls. I got used to being the heroine at a boys' school; everyone looked up to me.
It had a very kind atmosphere, because of the people who were in charge: David and Dorothy Watts. They were devout Christians who believed in a strict moral code but knew that you could be kind at the same time. You knew how far you could go, but overstep that and you were in trouble. And it worked.
There was no management through fear. That, I think, has influenced my own management technique. The way that they ran that school is the way that I would aspire to run a company: kind but strict, disciplined but interested in people, and there to help them if they are in trouble.
I probably stayed at Kingsmead a bit too long. I loved it so much they let me stay there until I was 12, so I came late to Cheltenham Ladies College. I was unhappy at Cheltenham. It wasn't the teachers but the boarding; I found it very restricting being locked up at weekends, and there was a lot of in-fighting. If you put a whole load of girls together and lock them in with nothing to do, they get bitchy because they are bored. Boys are much more straightforward; they just bash each other and then make it up. Girls really stick the needle in. I see it in my own daughters.
I didn't like this, and I just wanted to be at home. I missed my parents and thought, "Why am I here?" When I was 14 I got back to school for the summer term and it was still just as awful as ever, so I ran away. I was stopped by the police boarding a train for Cheshire.
The first person I went to after I left Cheltenham was Dorothy Watts. My mother and I went to see her and she was terribly, terribly kind. She said: "You've just got to put it behind you; you are just a normal child." (There were one or two suggestions from Cheltenham that if I didn't like it there must be something wrong with me.) Mrs Watts told me just to look forward, to get on with it, go to Birkenhead High School and it would all be fine. And indeed it was. Birkenhead was a girls' public day school trust, and was a very academic school; all the girls spent their time swotting. But there were also girls who got pregnant at 16 and left, and that variety made it a better school, I think.
I was in the choir and the junior house hockey team, and I did drama productions. In 1976 my father was standing as a candidate in a by-election and I did a lot of campaigning for him. He was a Liberal, so they didn't win, but it was great fun. I was meant to be doing my O-levels at that time. I didn't get desperately great grades, but nor did I get bad ones.
Stephen Lee was a big influence at Birkenhead. He was my history teacher, and he taught me for history A-level, history special paper, both the general papers, and Oxbridge history in seventh term, so he was a very important figure. I got glandular fever just before the A-levels. I was at home for two months - February and March but had to take my exams in May, so I really needed him.
He was a very quiet, gentle person. I really enjoyed talking to him because he was a deep thinker, very much like my father. They were both very kind, empathetic people.
I enjoyed my time at Birkenhead, but it was Kingsmead that I really loved. I chose my children's school because the headmistress is a scientist and used to teach at a boys' school. She describes it as a boys' prep school for girls.
Nicola Horlick hit the headlines in January when she was suspended as managing director of the UK pension fund at Morgan Grenfell Investment Management. The mother of five children, she was dubbed "superwoman" by the press. Her autobiography, Can You Have it All?, is published on 24 October (Macmillan Pounds 16.99), all proceeds to Great Ormond Street Hospital