The passion for wild animals began at an early age for Virginia McKenna. ‘When I was five, my father made me dress up in my best party frock and recite the old music-hall song Albert and the Lion for any visitors. I hated it, but I think everything started there.’ She wasn’t to know it then, but lions were to define her life. In 1966, she and her late husband, Bill Travers, starred in Born Free, the story of Kenyan game wardens Joy and George Adamson, who adopted Elsa, an orphaned lion cub, and then successfully released her into the wild. The Oscar-winning film was crucial in changing attitudes about animal conservation. Following this, she and Bill founded Born Free, the charity that rescues and rehomes animals taken from their natural environment. Which is why today, in slamming 40˚C heat, we’re in Shamwari, a game park in South Africa’s Eastern Cape Province.

For 10 years, Virginia campaigned for the release of big beasts from the antiquated zoo in Monaco, set in the cliffs below the palace where Prince Rainier and Princess Grace once ruled. With cruel irony, the animals’ prison overlooked tax-exile wealth super yachts and the Monte Carlo casino. With a determination that belies her frail frame and 77 years, Virginia persuaded the new ruler, Prince Albert, to release 16-year-old brother and sister leopards Pitou and Sirius, who have only known life behind bars. In a moment, they’ll be freed from their cages into a fenced-off garden of acacia trees, where they’ll spend the rest of their days.

Captivated by Virginia’s burning commitment, Prince Albert has agreed that his other wild animals will also be freed, and plans to transform Jardin Animalier into a petting zoo, with smaller creatures for children to stroke.Virginia says: ‘Our bush camps in South Africa allow the rescued lions and leopards, many of them victims of human abuse, the space and privacy to lead their lives as naturally as possible. We also teach students the importance of conservation. We want to instill in them compassion towards wildlife, so the future of our natural heritage can be sustained for generations.’ Virginia was the star of heroic post-war films such as The Cruel Sea and Carve Her Name with Pride, in which she played the quintessential young Englishwoman, although, ironically, she’s half-Irish.

At the height of her fame, she surrendered the glamour of Hollywood to start Born Free. It began with £2,000 of public donations, after the tragic death in London Zoo of an elephant named Pole, who had appeared in a film she made in Kenya. Today, the charity spends £3 million a year on rescuing and releasing animals into the wild, from England to the Far East. It also gives aid to impoverished villages in the Third World, in the hope that, in return, the natives will help Born Free protect their wild animals. When people talk of the sacrifices she has made, she says: ‘What sacrifices? I’ve been privileged to work with wonderful animals and have gained immense happiness when we’ve managed to give them back dignity, happiness and space in their natural environment.’

Two years ago, she was made an OBE for her animal-welfare work, but many of her supporters are anticipating the day she will be made a Dame. Virginia says it’s not an honour she wants. ‘It would disconnect me from all of Born Free’s supporters.’Virginia, who now has nine grandchildren spread around the world, shows no sign of slowing down. Her next campaign is tackling animal cruelty in China. Bejing is proving difficult. But this is a woman who, as the governess in The King and I, brought Yul Brynner to heel. Don’t bet against her.For further information about Born Free’s Big Cat project, visit www.bornfree.org.uk