The great and the grown reveal earliest memories

For Tony Blair, it calls to mind the painful sight of his father having a stroke, while Michael Grade remembers a famous opera singer collapsing in a deckchair in his back garden.

The notion of childhood has inspired more than 30 of Britain's most famous figures to contribute their most vivid memories to a unique exhibition celebrating the 50th anniversary of the Anna Freud Centre in north London.

Mr Grade writes of life with his father, Lord Grade: "I can remember the funny moments first – the great tenor Richard Tauber sitting in our garden one summer when I could have only been four or five, and splitting the deck chair in which he was sitting. We all laughed – so did he."

Tory heavyweight Ann Widdecombe remembers how, when she was five, her family moved from Portsmouth to Singapore, so that her father could take up his position at a Royal Navy armaments depot. Her grandmother, who lived with them, was told by doctors to stay behind for fear she would not survive the temperatures.

The poet Wendy Cope's memory of a family christening illustrates the vulnerability of small children. "There were lots of grown-up visitors. They went into the lounge to have tea. Someone shut the door and I was left outside. I tried to open it but I couldn't reach the doorknob. I was two-and-a-half."

Other memories relate more directly to their subjects' achievements in later life. Luc Vandevelde, the chairman of Marks & Spencer, remembers forcing himself to get up in the middle of the night, aged six, to accompany his greengrocer father to a market.

Julia Fabricius, director of the Anna Freud Centre, found the results of the exercise intriguing. "The fundamental nature of childhood in influencing how we turn out in later life is, in our view, under-rated," she said.

"The memories one holds on to are certainly part of the overall impression we construct of ourselves. Mike Leigh's memory is intriguing: he looks back at family photos and, using an adult's perspective, shows that he can tell the children in the picture are not necessarily happy."

The anecdotes, some profound, others more slight, but all undeniably personal, will be displayed at an exhibition in the neighbouring Freud Museum from Saturday.

The centre was founded by Anna Freud, youngest daughter of Sigmund and one of the world's pioneering psychoanalysts. It received a bequest from Marilyn Monroe.

John Cleese, Actor

"My clearest childhood memory is of standing at the end of our garden in Weston-super-Mare. One morning I saw a man wielding a sledgehammer. I could not believe that there was a delay between seeing the striking of the rock, and hearing it. It was my first realisation that the physical world is not what it seems."

Joan Bakewell, Broadcaster

"It was my fifth birthday and we were sailing from Southampton on the RMS Alcantara to Buenos Aires. As we pulled away from the quay there was great gaiety, crowds on the dockside cheering and laughing, throwing coloured streamers and balloons. I believed that the celebrations and the crowds were all in honour of my birthday. My parents didn't disillusion me."

Tony Blair, Prime Minister

"In many ways, I had a very fortunate, happy childhood. But I suppose the event I remember most clearly was my father's serious stroke when I was 11, which left him unable to speak for a long time. It underlined for me the importance of family and friends.

"As for my own children, I want them to remember they felt secure and were loved and supported in what they wanted to achieve in later life."

Alan Titchmarsh, TV gardener

"I thought it would be great to have a sort of wildlife sanctuary in our back garden. My sister and I had two rabbits, Lulu and Wilmer, and I reasoned that adding to them would not be too difficult if I had a shed with hutches inside. But sheds cost money. So I built a greenhouse. It was a simple structure, and inside it I grew half a dozen geraniums, a couple of spider plants and a false castor oil palm.

"I had two mice in a cage, just to keep the animal dream going. One morning I rolled back the polythene door, only to discover that a cat had got in during the night and frightened the two mice to death. Thinking about it, this is probably the one event that influenced my decision to be a gardener rather than a vet – plants clearly had much stronger constitutions."

Susan Greenfield, Scientist

"For 13 years I was an only child, and until my brother was born I was my parents' 'little star'. I am sure that my mother and father gave me the confidence to do all that I have been able to achieve in my life. They did not have the chance to stay on at school but they always tried to help me with my homework.

"My father loved machines and he liked repairing our old car and getting it ready for family trips out at the weekend. We used to take picnics into the countryside and to places like Heathrow airport to watch the planes. We went on holiday every summer to the seaside at Brighton or Eastbourne, but we never went abroad."