'˜I want to be the next David Attenborough'

But that’s where the connection ends. He’s never met his more famous namesake, and his life couldn’t be further removed from that of the X Factor impresario.

In his all-encompassing job as head of his charity Wildlife Aid, he’s been bitten by hedgehogs, gored by deer, and had an owl’s talons embedded into his scalp while on air - many of these anecdotes are charted in his memoir, My Wild Life.

Cowell had to rebuild the rescue centre after a blaze in 1996, caused by a faulty freezer, razed it to the ground, but remains undeterred and passionate about his cause.

A forthright, witty character not averse to swearing - charity patron Ricky Gervais once described him as ‘David Attenborough with Tourette’s’ - Cowell is a rocket, one moment rescuing foxes, badgers, birds or other creatures with his team of 350 volunteers, the next rallying to raise funds or starting a new campaign.

He rarely takes a holiday, works seven days a week, and admits his long-term girlfriend Stani puts up with a lot.

“I’m like a blunderbuss! I’m all over the place but I love the challenges, especially when you are rescuing something. You never know what you are going out to. It’s all about thinking on your feet.

“This morning we had a call about a deer with a broken leg, I went out to look at a fox, it’s been mad.”

He always talks calmly and softly to the animals he is rescuing.”

Hundreds of animals are housed at his centre at any one time, including injured ones and orphans, nursed and fed until they’re fit enough to be released.

He has strict rules never to befriend them, because as soon as they develop a relationship with a human it drastically reduces their chances of returning successfully to the wild.

Cowell’s latest vision is to build a wildlife hospital, next to a commercial veterinary hospital near a major teaching unit with wetlands and marshes (he needs to raise £5.5 million).

It’s a far cry from his life in the Eighties as a commodities trader in the City, making huge amounts of money and living the high-rolling lifestyle that went with it. He admits he neglected his (now ex) wife Jill and didn’t see his two daughters grow up. “Looking back, I loved money,” he reflects.

But while his colleagues blew their bonuses on designer gear, in 1980, Cowell set up a wildlife sanctuary in the grounds of his stockbroker belt home in Leatherhead, Surrey, which, seven years later, became Wildlife Aid.

In the early days, Jill ran the centre during the day, and Cowell would go out on rescues at weekends. But the strains of working in the City took their toll - “The pressure was just horrendous and it creeps up on you, and it all went hugely wrong” - and he suffered two nervous breakdowns.

“They called it executive burnout; I rather like that,” he muses. “I blacked out on a train, then went to pieces and they kept taking me to hospital. I just cracked up. The thing that nipped that in the bud was when I was fired. I felt my shoulders rise about six feet higher than they had been.”

He was eventually sacked, and only then did he realise that rescuing animals was really what he wanted to do.

At 42, Cowell answered his calling. Not only did he run the charity, but he also presented, wrote and produced Channel 5 and Animal Planet series Wildlife SOS for 16 years until the show was axed.

Demands for more sensational wildlife stories are ever-growing, he says.

“They want the stupid stuff, the man being bitten by an alligator, or something ridiculous happening, which I think is sad. We need to portray wildlife with reality.”

He says around 70% of the animals which go into his rescue centre are released back into the wild. :: My Wild Life by Simon Cowell is published by Michael O’Mara, priced £12.99. Available now