Me and my dad, Spike

Even when Dad was at home, out of the limelight, he was funny and zany - his banter was constant and we would all end up crying with laughter. There were lots of dinner parties when the likes of Peter Sellers and Britt Ekland would sit up all night talking, with Dad holding court - it's a very Irish trait.

He knew lots of famous people - Prince Charles and John Lennon were fans.
It was a privilege to be Spike's daughter. I believed in pixies and fairies - I saw them, that's how real he made them. We would have tea parties and we would all get mini letters on tiny pieces of paper in tiny envelopes from them, made by Dad.

Once, on my birthday, he telephoned me in the middle of my party, pretending to be the fairy king. He told me there was a present wrapped in a rose petal at the bottom of the garden. My friends and I went tearing down there. Inside the rose petal was a golden bird cage with a tiny golden bird inside.

There was a note with it, from the fairies, saying they had been working on it for days. When I stopped believing in Christmas, I got woken up in the early hours by Mum. "Santa is in the garden!" she shouted. And there he was, in the snow, with a beard, a red suit and a sack on his back.

But we all knew there was a dark side to him. He felt up against the world, as if he were battling against things that were wrong. As he got older, that got harder for him.

He was diagnosed with manic depression and the rest of us - Laura, Sean and Sile, his children by his first wife - all suffer mild forms of the illness. Dad would talk to me about it and say, "It's the nature of who you are. You will see sunsets in a special way, you will see life in a special way. The Milligans are like Arab racehorses. We'll kick the stable to pieces, but we'll always win the race."

He taught me compassion; the love he had was enormous. Whales, tigers, donkeys - he would save anything that didn't have a chance in life; nobody knows how many animals he saved. He'd invite deprived young people to stay at weekends. He was a pioneering vegetarian, but we children were free to choose.

We lived in a beautiful house, Monkenhurst in Barnet, which my parents discovered in 1974. It was a five-storey folly with three floors of stained-glass windows. It was a grand property but they did it up very cheaply. People might think the house would be chaotic, but it was immaculate.

Dad was going through the peak of his illness in 1962 when he married Mum, Patricia "Paddy" Ridgeway, a star of West End musicals. She took him on when she was 26 and he was 44, already had three kids and was suffering from manic depression.

She sacrificed her career for her family; she was just about to sign a record deal with Decca when they married.

She protected him, and us. When he was really bad and up in his darkened room, he would send a Post Office telegram saying "TOAST PLEASE". Mum, who had a great sense of humour, would send a telegram back saying "ON ITS WAY".

Occasionally, he would have had enough of the world. There was a stage, long before I was born, when he was suicidal but he couldn't go through with it.

He went through hell. When he was really low he would put a sign on his bedroom door (he didn't share a bedroom with any of his wives) which said: "Go away", but I knew I didn't have to go away; the sign was not meant for his children. We were the only ones allowed to take his dinner in to him. For anyone aged over 20 the frown would come. But for us the smile was there - he never inflicted his suffering on us. I've never known a love like it.

Mum and I adored each other. I was her only child, though her step-children all called her mum. I was 11 when she died in 1978 at the age of 43, just when we were becoming friends, not just mother and daughter. She had had a mastectomy in 1973, but had gone into remission for several years. I didn't know she was ill, although I do remember tickling her one day, and discovering her breast wasn't there.

When she knew she was going to die she took me to New York that July for a month's holiday. We went to Long Island and had an idyllic, heavenly time, having picnics, being by the sea. She was trying to give me a good farewell, to show how much she loved me.

When we got home the cancer got serious. By Christmas, she was obviously very sick - dad and I had to help her down the stairs. She died at home with the family around her. After that, Dad suffered great depression, but he was never aggressive towards his children - he kept his unhappiness private. It took him years to recover. He grieved when Peter Sellers died two years later but he didn't fall to pieces and kept working solidly.

When he remarried in 1983 - to Shelagh Sinclair, whom he met when she turned up as a secretary to take dictation - he definitely found some peace and happiness. We'd spend priceless hours laughing. He had a complete inability to deal with objects - we would witness the most hysterical scenes with cars.

I remember being on holiday in Athens with dad and my sister. He spotted a mosquito in our hotel room, so he cleared us all out and charged back in there with a rolled-up newspaper. He spent half an hour smashing the place up as we waited patiently outside. When he came out, his hair was everywhere. "Got it!" he said. The room was trashed.

My father was my hero. When he died, I woke up feeling orphaned and lonely. I'm envious of the people who are with him now - I'd love to hear him, Peter Sellers and George Harrison having a jam. Last week I had to sing at an audition and I could feel him there, rooting for me.

When I decided to become an actress he was so supportive. He used to say: "Your mother had it, I've got it, you've got it and I'm very proud of you."

I'm so happy to be in the new film of his 1964 best seller, Puckoon; I play Mrs Madigan. It would be so sad to see his work ebb away. There is nothing I can't deal with thanks to my dad, nothing."

Puckoon opens on Friday.