Chris Packham has just finished putting together a piece about the peregrine falcon for Autumnwatch, filmed from the dizzy heights of the tower above the House of Lords. "I used to warden a pair during the 1970s because there were so few birds left," he exclaims, breathless with enthusiasm, "but now, there are 22 pairs just in London alone. It's an amazing success story."
To find out what the peregrines have been eating, Packham has been busy sifting through their droppings, "CSI-style", and has unearthed a surprising find. "As well as the usual prey like pigeons, moorhens and blackbirds, we found the remains of an African grey parrot. They are becoming much rarer in the wild now. This one probably escaped from London Zoo so it would have been easy prey for a peregrine. If the keeper is watching, he is going to get a shock."
Getting a peregrine's-eye view of the capital and then dissecting its prey is exactly the sort of activity which has made Packham a favourite with the four million viewers who regularly tune in to Autumnwatch. And it is also why since he took over the anchor role from Bill Oddie more than a year ago, he has rarely been off our screens or out of the headlines.
It is a feat he has emulated throughout his 30-year career, fronting 550 wildlife programmes and counting. His big break came 24 years ago when, at 24, he began presenting the children's television programme The Really Wild Show, complete with a shock of blond spiky hair. It was modelled on Billy Idol, whose hit "Rebel Yell" could have been written as an anthem for Packham's life. "It was a dream come true. I played football with a cheetah, married a king penguin, and got to handle a range of venomous snakes".
I first met Chris in 1988, when I joined the show as a researcher. Back then, with his rock-star looks and outlandish fashion sense, he was hugely popular, getting twice as many letters as his co-presenters, Nicola Davies and Terry Nutkins, combined. Predictably, most were from teenage girls, but there were also some from older women and gay men. And a few always included a scantily clad photo or an item of lingerie, much to the titillation of the production staff. "It was very flattering, particularly as I've never had a very high opinion of myself physically. I can understand why women would send lingerie to Brad Pitt or Johnny Depp, but not to me. I always thought they were wrongly addressed. But they can't have been, because I still get the occasional suggestive letter on Autumnwatch."
Over the nine years Packham fronted The Really Wild Show, he grew up in front of the cameras and sometimes found the attention difficult to handle. "I never wanted to be on television but drifted into it because of my love of wildlife. Looking back, I was an angry young man. But that was useful because I turned my anger into motivation. I'm still a bit like that today in that I don't easily take no for an answer."
Back in the late 1980s, the BBC Natural History Unit was a clique which Packham found it difficult to fit in with. "I had a lot of doors slammed in my face because I looked different." More than 20 years later, I put it to him that the unit is still a closed shop, because all the people we used to worked with are still there and they now hold senior positions. Unsurprisingly, new people find it difficult to get in. "It was a clique, but so was the whole of the BBC. Going way back, it was a public school institution. But it is changing. We have a really nice guy working on Autumnwatch called Lindsay. He sent a film in to the programme a few years ago and now works as a cameraman. He comes from a working-class family in the Lake District. So, against the odds, some of my generation have managed to sneak in through the back door and now we're going to hold that door wide open for them".
Today, it is no longer the BBC hierarchy which gets him angry, but the trend for natural history programmes to be fronted by celebrities who know nothing about wildlife. "It might awaken an interest in some, like Stephen Fry, who is clearly a very intelligent guy. But picking celebrities and chucking them in front of wildlife is a bit like taking me and putting me in front of the opera. I would be sat there with my Walkman on listening to The Clash. When Alan Titchmarsh became flavour of the month at the unit, someone said to me he knew more about grass than grass snakes."
With a change of government, I ask him about the looming spectre of cuts to the BBC and the proposal to give some of the licence fee to other broadcasters, such as ITV, to fund wildlife programmes. "Natural history broadcasting is a cornerstone of the BBC. I'm interested in quality but I do fear for the future of the BBC. I get upset about ITV companies whingeing they have no money, because that is the market they are in. Their advertising revenue will pick up when the economy does. It's survival of the fittest and at the moment, we are fit enough to make the best programmes."
Packham's aim in life has been to educate the young and enthuse them about conservation. But he is no fan of David Cameron's big idea of a National Citizen Service, which could see every 16-year-old doing two months' community work, including on conservation projects. "When I was 16, if someone told me what to do I'd tell them to get lost. Is 16 the best age to ask people to do that? It's not easy when you've got scrambled hormones and you don't know what you're doing with your life. It's too much like national service. We should ask our youth to do things, not tell them."
If anything has mellowed him over time, it is not age but stepfatherhood. "Once, I couldn't wait to get away. But Megan changed all that". Megan is his stepdaughter from a previous relationship and is 15. He is still very close to her. "It's taught me a lot about giving. I've taken her all round the world. We've visited art galleries, temples and gigs and talked about everything from religion and politics. I hope I've given her life some context so she can understand who she is. I've no focused ambitions for her. As long as she is a well-rounded individual, then I'm happy. And I've enjoyed every single minute of it."
He is also proud of Autumnwatch and its sister programme, Springwatch. This year, he is travelling throughout the country with his co-presenter Kate Humble in search of inspiring wildlife stories. Another source of pride is how he helped to raise more than a million pounds for conservation projects when he fronted the Wild Night In programme at the end of the last season of Springwatch. In the next few months, he will be working on a programme looking at how the money has been spent. "It's a good example of the BBC giving something back. I'd like to see a Wild Night In broadcast once a year and become a regular fixture like Children in Need. All the money will go to carefully vetted causes and it will make a real difference to conservation projects here in the UK and around the world."
Throughout his career, Packham has never fought shy of speaking his mind, occasionally to the discomfort of his BBC bosses. In the past year, this has seen him credited in the media with waging war on pandas, dormice, insect-eating celebrities and, most recently, tigers. Although he insists he is often misquoted, it is not something he is going to apologise for. "I don't court controversy for the sake of it, but I do want to start a debate. Take I'm a Celebrity... Get Me Out of Here. Why should bugs be eaten for our entertainment? It really upsets me. I like life."
And that is what makes Chris Packham so special. He is not on our screens because he wants to be a famous presenter, but because it gives him a platform from which to shout about what really matters to him: conserving our rapidly vanishing wildlife. Before we depart, I ask him what is the most important part of his job. "I want to be a pleasure to work with. These days, I carry the tripod and make the tea and try to be in the right place at the right time to make everybody's life easier." That, at least, will be music to the ears of his BBC bosses. Now all they need to do is love the rebel with a cause.
'Autumnwatch' is on BBC2 on Thursdays at 8.30pm