I had a happy childhood. My dad, Donald, was a vet and had a practice in Yorkshire. Cats and dogs were his bread and butter, but his greatest love was large animals. I used to go out on his rounds and it was a very James Herriot existence. But when I was 10, he was injecting some piglets and the sow, which had been locked up elsewhere, got out and battered him. He was in hospital for a long time and visiting times were quite strict, so I'd write and tell him what I'd done at school. That's when I started writing diaries.

My aunty says I'm the double of my father. He was a workaholic, which I've definitely inherited. And like me, he could be the life and soul of the party, but also quite withdrawn. He grew up on the island of Tiree in the Hebrides and Gaelic was his mother tongue. His father was a crofter and Dad was the first in the family to go to university. He taught me the bagpipes and my rekindling of my love for the bagpipes is partly that point of connection.

Dad had been frail for years but it was a shock when he died. On the day he took a turn for the worse, I was competing in the London Bikeathon for Leukaemia and Lymphoma Research. As I was cycling and worrying, this young guy came alongside me and said: "You're the reason I'm doing this race. My dad died of leukaemia and I heard you talking about how you got involved when your friend died." As he said it, I just knew Dad had gone. When I phoned Mum, she said he'd died halfway round the race. I was in a daze for days. One of the nicest letters I got was from Gordon Brown, who, for all our ups and downs, talked about the impact his father's death had had on him.

My mother Betty is 86 and fit as a fiddle, though she still worries when I hit the headlines. One of the reasons I haven't done a full-time job since leaving politics is that I sort of promised her I wouldn't. What little excess weight she had, she lost worrying about me. Iraq was terrible for her. When I was under the cosh at No 10, I'd tell Tony [Blair] that Mum was in a real state and he'd phone her up and have a little chat.

I met my partner, Fiona [Millar], at the Tavistock Times when we were on the Mirror training scheme. We were both 21. She was easily the best-dressed reporter, with a fantastic bum, which she still has. She was also bright, feisty and had a car. The attraction was instant and within weeks we got a flat together.

Fiona didn't want me to work for Tony. When I got the call, we were holidaying in France, her dad had died and she'd just given birth to Grace, our third child. But I knew I had to take the job. The thing that drove Fiona mad was the phone going. She called it the radar. She was supportive most of the time, but we had a fundamental disagreement over Iraq and it became very personal. But we've been sustained by a really strong commitment to each other and neither of us are quitters.

We've never married. To me, marriage is partly a religious thing and I'm not religious. With Fiona, it's more about the feminist thing. But there have been times when we've thought about it, and Grace is quite keen. Who knows?

All our kids are affiliated to the Labour party and are much more political than I was at their age. When I was at No 10, I missed the odd parents' evening. But when Fiona and I are long gone the boys will be able to say they played football with Tony Blair at Chequers. And Rory, my eldest, met Bill Clinton at a Labour party conference. That stuff matters.

Interview by Angela Wintle

Alastair Campbell's fourth volume of diaries, The Burden of Power: Countdown to Iraq, is published by Hutchinson, £25