Mark Thompson: Screen saver

Among charges that cannot be levelled against Mark Thompson, the beleaguered director general of the BBC, are that he is aloof and uncommunicative, cringing sullenly in his ivory tower as controversy rages about him..

Arrogant? Maybe. Inconsistent? Arguably. Mealy-mouthed? Which public figure is not? But as for accessibility and accountability, it has been hard to flick the on switch of the radio this week without hearing his earnest, studiedly classless voice defending himself and his organisation against a two-pronged assault – first from those who want to see him share the licence fee with other broadcasters (known as top-slicing), and then from people who resent that same fee being blown on £100 bunches of flowers and bottles of champagne for stars who can well afford to buy their own.

On Wednesday he was interviewed at length on Radio 4's Media Show about top-slicing. Then yesterday morning he was subjected to a long interrogation on the Today programme about his and his colleagues' expenses, followed almost immediately by a similar ordeal on Radio 5 Live, where Nicky Campbell asked him why it was necessary for a man earning nearly £800,000 a year to claim for car-parking charges: "You get so much anyway." (His answer was that it wasn't really him; it was his chauffeur.)

The ethics of taking chunks of your organisation's air time for special pleading on your own behalf are questionable. Cynics might compare it with the compulsory circulation of the thoughts of the supreme leader of a totalitarian regime – even though those BBC employees who get the dubious honour of interrogating him make a show of asking him tough, gritty questions. Thompson calls it openness: others might see it as propaganda.

Controversy, of course, goes with the job. His five years at the helm began when he was parachuted from Channel 4 in 2004 to replace Greg Dyke, who had resigned following the Hutton inquiry's criticism of the BBC over the "dodgy dossier" on Iraq's non-existent arsenal.

The past nine months have been especially contentious, beginning with the row over Russell Brand's and Jonathan Ross's offensive telephone messages to Andrew Sachs, which in turn reignited the issue of stratospheric salaries being paid to star presenters. Then in January came Thompson's refusal to allow the broadcast of a charity appeal for the victims of the conflict in Gaza, on the grounds that it might be seen as overly partisan. Convinced that it was the right decision, safeguarding the BBC's reputation for impartiality, he stubbornly resisted the strong political pressure to reverse it.

Some of that unshakeable conviction and tough resolve no doubt stems from his education at Stonyhurst, the Jesuit boarding school in Lancashire. From there he went to Merton College, Oxford, where he won a special prize for English. Soon afterwards he joined the BBC as a trainee.

Singled out early on as a potential high-flyer, Thompson moved through a series of jobs in news and current affairs, serving on most of the major programmes of the time – Nationwide, Breakfast Time, Newsnight – until in 1988 he was made editor of the Nine O'Clock News. After a stint on Panorama, he assumed a number of executive positions, being made controller of BBC2 in 1996 and director of television in 2000.

This smooth, uninterrupted ascent of the corporate ladder, which would surely reach as high as the director general's office, was interrupted in 2002, when he was invited to apply to be head of Channel 4, replacing Michael Jackson. He was a natural choice, since his term as head of BBC2 had been widely admired: he had maintained the channel's audience share by backing such innovative comedy shows as The Royle Family, The Fast Show and I'm Alan Partridge.

The way he conducted the negotiations for the Channel 4 job highlighted his skills as an office politician. After applying, he learned that he was not the front-runner, so he decided to withdraw his application rather than be rejected. He was on the point of doing so when his rival, an American, dropped out, and his appointment was confirmed.

Nobody at the BBC regarded this as a defection. It was still thought likely that Thompson would become director general, and spending a few years with a commercial company would only strengthen his credentials.

Channel 4 is a more casual, less hierarchical organisation than the BBC, and Thompson responded to the environmental change by adopting the designer stubble and open-necked shirts that are now his trademark. He would have spent longer there but for Dyke's untimely departure; as it was, much of his time at Channel 4 was taken up with trying to negotiate a merger with Channel 5, which did not come about.

The way he left Channel 4 angered its chairman, Luke Johnson. He accused Thompson of being devious, in that he had promised to inform him of any approach from the BBC, but in the event did not do so. Johnson told Maggie Brown, the historian of Channel 4: "He's a good manager, Mark, but he's even better at his career management."

His colleagues respect him, even if they do not hold him in great affection. Unlike many heads of big organisations, he has no clique of trusted aides surrounding him. "He's a loner who keeps things close to his chest," says Dyke.

Living in Oxford with his American wife, Jane Blumberg, and their three children, he tries to separate his professional from his personal life. That strategy failed when it was revealed that he made the licence-payer foot the bill for flying the whole family back from Sicily when he had to break his holiday to make multiple apologies for the Russell Brand debacle.

While in his many radio interviews he presents an image of calm reason, he has occasionally been known to blow his top. Former colleagues at Channel 4 remember him using an unprintable scatological metaphor after a meeting with Tessa Jowell, then the minister responsible for broadcasting.

Greg Dyke believes Thompson has done well to sustain the BBC during a difficult period. At a time when all commercial broadcasters are suffering financially, the pressure to share the licence fee with them is sure to grow.

Last week's report by Lord Carter on the digital future added to that pressure. That is why the director general felt he had to respond to it in such sharp terms, pointing the finger at "a small group of people who have been ideologically focused more on the principle of getting a wedge into the licence fee ... rather than having a particular urgent need".

His critics say that he is himself partly to blame for this, having agreed to ring-fence part of the licence fee to fund the forthcoming switch to digital television and radio.

He seems determined, though, to hold the line there and fight ferociously against any further dilution of the BBC's position as sole recipient of the fee. Instead, he has suggested that the BBC might offer other media outlets free access to some of its news resources – an idea that has been greeted with little enthusiasm.

On the Today programme yesterday, Sarah Montague asked him why he needed such a high salary, seeing as he had a secure job in the public sector. He laughed at the assumption of security, pointing out that three of his four predecessors as director general – Alasdair Milne, Michael Checkland and Greg Dyke – had been forced out of office prematurely.

That fate is unlikely to befall such a canny and careful operator as Thompson, in part because there is no obvious successor. He has, too, made a point of forging good relations with the BBC Trust, the watchdog body that forced his predecessor out.

When he arrived, the watchdog was a Rottweiler, its mouth dripping with Dyke's fresh blood. Today it is a poodle, comfortably settled in Thompson's lap, contentedly wagging its tail in approval as he makes the case for keeping the whole licence fee to himself.

All the same, he may soon be seeking an exit strategy, especially if the decision on top-slicing goes against him. Dyke, who keeps in close touch with his successor, believes that the ideal term of office for a director general is from five to seven years. "I suspect he's into his later period," he declares.

And what then? History shows that ex-director generals find great difficulty in moving on from the top job in British broadcasting to anything remotely as satisfying. Do not be surprised if the steely and resourceful Thompson proves an exception.

A life in brief

Born: Mark John Thompson, 31 July 1957, London.

Family: Married an American academic, Jane Blumberg, in 1987. They live in Oxford and have two sons and one daughter.

Education: Attended Stonyhurst College, then Merton College, Oxford, where he graduated with a first in English.

Career: Joined the BBC in 1979 as a production trainee. Worked on Newsnight, and in 1988, at the age of 30, he became editor of the Nine O'Clock News. Subsequently edited Panorama, progressing to head of features, head of factual programmes, controller at BBC2, director of national and regional broadcasting, and director of television. In 2000 he left become chief executive of Channel 4, returning to the BBC in 2004 as director general.

He says: "Every one of these expenses in my view was reasonable and was justified. I don't believe that I've yet seen any evidence that a single one of these line-by-line expenses has been in any way unjustified."

They say: "He's a good manager, Mark, but he's even better at his career management." Luke Johnson, chairman of Channel 4