I work for ... Tamara Ingram Kirstan Lyall is PA to the joint chief executive of Saatchi and Saatchi

Nine years ago I joined Saatchis straight from secretarial school, aged 17. I was very lucky, because it was the only company I wanted to work for. It was a manic place running at a manic pace, a noisy, lively, youngish family, and I settled in quickly and easily. On my first day I left at 5.30pm promptly and the next day was gently told that I was really expected to remain until the day's job was done. I found myself working around the clock; there were times when I would be cabbed back home just to have a quick shower and pick up a fresh change of clothes; but I loved my role and got paid well for the overtime. My mother was worried; she runs an employment agency and was used to nine to five, so she rang Tam on several occasions to check up on me, but Tam reassured her by telling her how much she valued my team spirit.

Before I knew Tam I was petrified of her. Her office was a nightmare, with piles of paper and mess, and I didn't want to work for this fireball of a woman. But once I started working solely for her we got on famously. She said, "do what you like, darling", and I looked after her, becoming very maternal. If you're a successful man it's likely that you have a wife to organise dinner parties, children's parties, holidays and so on, but in Tam's case I am often the one who organises these domestic details, from buying food to rescuing her car when it runs out of petrol.

The responsibilities made me grow up quickly, for although I was the baby of the office I was also the mother hen, making sure that the 60 people within our account group were happy and keeping Tam informed if they weren't. Everyone feeds off the buzz and I feed off Tam, because she is rarely upset or down, has boundless energy and is always quick to make a joke. She's very inspiring, particularly when people are slogging it out to reach a deadline. Her walkabouts lift people's spirits and the fact that she's not very good at remembering people's names doesn't matter, because she calls everyone "darling" anyway. There's no one like her - except perhaps Edie from Absolutely Fabulous.

When Maurice and Charles Saatchi left, taking the top layer of management with them, Tam was made joint chief executive. Tam and her work partner Adam had to stabilise things quickly, since our clients were already being poached. We were all worried about losing our jobs but Tam and Adam were amazingly good at reassuring everyone by being very truthful and accessible.

I wasn't sure whether I could cope with the new responsibilities; I was still only 21, and since there was no one to hand over the job to me I found myself very much in the dark. The scariest thing was having to deal with all kinds of important clients for the first time, such as the chairmen of Toyota and Procter and Gamble and their high-powered corporate PAs. Coming from such a friendly and easy-going environment, I had to be as tactful as I could, but I adapted quickly.

Recently I and another PA were put in charge of organising corporate events for Saatchis' clients. So in addition to looking after Tam, providing her with full back-up and more, I now organise entertainment at Wimbledon, Ascot and Twickenham. Last year we organised the agency's party, "A Night of Eastern Promise", which was great fun. My now role came just at the right time; I needed to be re-enthused, as I'd got to the stage where I felt I could do my job standing on my head.

I have made a lot of friends within the company and regularly meet them at our office pub, called the Pregnant Man after Saatchis' first big ad. If I feel a bit cut off during the day I go on walkabout on behalf of Tam, gauging how everyone feels and chatting to any of the 600 people who work here - five-minute chats are never frowned upon. Tam likes to tease me by disappearing somewhere in the building herself and waiting for me to track her down. I often hear her saying to others: "My Kirst is so marvellous; how does she find me?" If I could keep her on a bit of elastic I would, but being good at my job means being able to read her mind. At the end of the day she often says to me, "Darling, what would I do without you?" I think she knows that the feeling is mutual.