Though Andrew Marr has spent much of his weekend hot-air-ballooning above the Glastonbury music festival and is about to devote an afternoon to pootling around in a "beyond valuable" 1906 Rolls-Royce Silver Ghost, he is distinctly troubled.
The source of his agitation is not his beyond-punishing schedule – of making his weekly television show, of radio broadcasting, of filming one after another landmark BBC television blockbuster series and then writing the book to go with it – or his battle to protect his private life.
His concerns are for the future of a vocation he once wrote a book about, the lovingly titled My Trade. Marr generously gets the coffees in and sits down in the Broadcasting House cafeteria at a table recently vacated by the Radio 3 controller, Roger Wright, and sets out his thinking.
"The thing that worries me most at the moment about the condition of journalism is, frankly, who's going to pay for the journalists and the journalism in 10 years' time? Teenagers, people in their twenties, even in their late twenties, have now got to the position where they wouldn't pay for news. They expect their news to be free, they expect it to be in a free newspaper on the underground or at the bus station or, more often, they expect it to be a free good on their laptops. My kids wouldn't dream of buying a newspaper – and we are a newspaper household."
Marr, 48, a former editor of The Independent who began his journalistic career on The Scotsman, is doubtful whether the internet is capable of generating the finance that will sustain high-quality journalism on a grand scale. "Newspaper groups are going online and hoping that somehow they can replace the lost revenue through online advertising, [but with] the numbers that I see, I just don't know how that's going to happen," he says.
"In the end, does it really matter if newspapers physically disappear? Probably not: the world is always changing. But does it matter if organisations independent enough and rich enough to employ journalists to do their job disappear? Yes, that matters hugely; it affects the whole of life and society."
Broadcast journalists like himself, just as much as print ones, are "under pressure to deliver quantity", he observes. The result is that the stories that hold those in power to account are in danger of being overlooked in a new world dominated by pontificating. "The business of funding digging journalists is important to encourage. It cannot be replaced by bloggers who don't have access to politicians, who don't have easy access to official documents, who aren't able to buttonhole people in power," he says. "I'm a great believer in the direct quote in quotation marks and the hard fact. In the blogging world there is a vast, swirling typhoon of comment, grandly called analysis. A reporting journalist is someone who is paid to spend lots of time asking questions, reading, going back again. Anyone can produce words but you need a system which pays journalists to spend time to find stuff out."
Marr has in mind the legacy of his "journalistic mentor", Anthony Bevins, the first political editor of The Independent, a maverick figure of the House of Commons lobby who kowtowed to no politician and produced such history-defining scoops as the challenge to Margaret Thatcher's leadership and the secret talks between John Major's Tory government and the IRA.
"What he was particularly famous for was that he read the reports, he went through the back pages, he double-checked the indexes, tried to find out where the figures had been massaged and worked with MPs who put down lots of parliamentary questions. It's that style of old-fashioned, meticulous, digging journalism, that has nothing to do with celebrity. Tony could go weeks without producing a big political story, because he was working on something that was really going to change things."
Marr's own style of interacting with politicians is different. An outstanding communicator, who confounded those critics who doubted whether he would be able to translate his elegant writing style to broadcast media, Marr has done more than most to stem the tide of public apathy towards British politics.
Though he concedes that he is no journalistic attack dog, he maintains that a bare-fanged frontal assault is not the only effective tactic of a political interviewer. "You can get as much out of people a lot of the time by drawing them out and by asking what might be slightly acid questions in a friendly and cheerful way. It's sometimes harder for a politician to refuse to answer or to dodge away if you are smiling at them and looking them in the eye. That's about technique but it's also what I'm like – I am absolutely less naturally confrontational than Jeremy (Paxman)," he says.
"One of the things I've learned is that if you try to be a different person on television than you are in real life then the viewer knows there's something not right. I am probably a sunnier person than Paxman and I am no Welsh terrier," he says, a reference to John Humphrys.
But, he argues, no pussycat either. "I can be exceedingly aggressive when I want to be," he says, claiming that encounters with Gordon Brown and Alistair Darling on his Sunday morning BBC1 programme, The Andrew Marr Show, "were as aggressive as any interview you will have seen for a long time".
Having earlier broadcast Radio 4's Start the Week, Marr is set to depart London to do some filming with the vintage Rolls, a sequence that will form part of a major series, provisionally titled Britannia, examining this country's history between 1900 and 1945, a follow-up to the hugely popular Andrew Marr's History of Modern Britain. The six one-hour programmes will not be screened until September 2009. "We have to start making it early because there are so many other projects I'm involved in," the presenter explains, adding that he is already "two-thirds through" the book he is writing to accompany the series.
In the back of a car headed for Northamptonshire, his thoughts return once again to Tony Bevins, whose reputation lives on in the form of the Bevins Prize for outstanding investigative journalism, which will be awarded later this year at the Society of Editors conference. The prize is dubbed the "Rat Up a Drainpipe" award, in memory of Bevins's catchphrase for flushing out a killer fact. "He could be incredibly abusive to politicians, but had very strong ethics and believed in uncovering stories, particularly about money, influence peddling, corruption. Tony got some extraordinarily big scoops, but died horribly young and in pretty bad circumstances. He was charismatic. You adored him or you hated him. And I adored him."
Marr, also the former political editor of the BBC, believes that in political news coverage there has been a discernible shift from policy stories towards reports focused on personalities. "We've had huge numbers of stories about the extent to which Gordon Brown is depressed, gloomy, not sleeping. We have had lots of analysis of David Cameron's media strategy and style, all of which is interesting and important up to a point – but I worry how much is being slipped through in terms of policy changes."
Policy stories are "a bit tougher, a bit drier and duller", admits Marr. "Yet, they shape everything around us: the speed we are driving, what we are driving and how many emissions we are putting in. Politics ruins a lot of lives, and it makes a lot of lives much better. We need to keep fighting for and defending the space to allow proper discussions of all of that."
He is visibly depressed by the thought that "people in their teens and twenties" appear to favour heat magazine and similar titles over quality newspapers as sources of news. "We all enjoy the vividness and immediacy of human stories and gossip. But it's entertainment, it's not journalism – or at least not what I think of as journalism."
Marr counts himself as a "celeb" these days. Along with the likes of Pixie Geldof and Kate Moss, he was a target for photographers as he tramped across Glastonbury in his wellies. He was also there to film for Britain From Above, which will go out in three parts on BBC1 in the autumn. The project was inspired by the popularity of Google Earth and "programmes like Coast and Blue Planet, which have a visual gorgeousness about them," says Marr. "It applies some of that spectacle and 'wow factor' to something that would dryly be called sociology or human geography. It's not going to feel like human geography, it's going to feel like fun television, I hope."
Glastonbury, he argues, mirrors British life. "I thought Glastonbury worked as a metaphor for the rest of the country. It's got a perimeter, it's muddy, it's chaotic, it's crowded, it's cheerful, and it's got a transport system which is struggling to survive."
Next year, Marr will host another mammoth BBC project: three 60-minute films on BBC2, coinciding with the 200th anniversary of the birth of Charles Darwin. "I'm not doing a straightforward history. This one will be a much more argumentative and, I think, edgier series about the social and political implications of evolution, which is not a cosy theory at all."
Marr, who championed Darwin in the BBC's Greatest Briton project, is president of the Galapagos Conservation Trust, which exists to protect the islands that helped inspire the theory of evolution. "You should only go once, because the pressure of tourism on these very delicate islands is very worrying," he says. "It's an extraordinary, very fragile and unique ecosystem, and the trust is there to try to balance the needs of local fishing and tourism with the overwhelming human and scientific resources there."
As he works, he absorbs facts. Start the Week requires an enormous amount of preparation but, as a consequence, "I know as much about what's going on in the world as I have ever known". How does he fit everything in? "It's almost impossible," he says. His frequent jogs across south-west London parks are a means of "de-stressing". As he runs, his famously protruding ears are rigged up to an i-Pod that pumps out a "strange" Marr megamix of REM and Handel arias.
As he departs, this chronicler of Britain, in its present and in its recent past, offers up his "fact for the morning" as a way of describing the relative fortunes of Britain and America in the past century. In 1910, Britain still produced 10 times as many bicycles as America, but America produced 10 times as many cars, "which tells you all you need to know," Marr says, as he heads off up to the motorway to find his camera crew and his vintage Roller.
Entries for the Bevins Prize close on 11 August. Details at www.bevinsprize.org