Review: This film makes a thriller out of British terrorism - but one that cuts too close to the bone

Britz, Channel 4; The Genius of Photography, BBC4; Long Way Down, BBC

Channel's 4 publicity team sure know how to pick 'em. Trailing Britz, their new lavish two-part drama, they presented its protagonists: a boy, working for M15 and a girl, pursuing violent terrorist extremism. Underneath these two was the unforgivable slogan: "Whose side are you on?" It's hardly a legitimate question, and presenting it as if it were contributes another Lilliputian flint to the arrowstorm of moral confusion playing round our heads. The film itself was troubling. I admired its spirit of inquisitiveness - of course we need to ask why British Muslims might turn towards extremism - but its slick style turned my stomach.

Peter Kosminsky, the director/writer, won a Bafta last year for The Government Inspector. Now he brings us this bloated epic, four and a half hours long. It belongs to that most uncomfortable genre: the "relevant" thriller, in which real and ongoing problems, places, and events are spliced and diced for maximum dramatic effect. In Britz, familiar names (the 7/7 bomber Mohammad Sidique Khan, for example) and settings (the Docklands Light Railway) are used as part of the set dressing, while the plot is full of chases, twists, and incredible coincidences. I am not, I think, the only person to find nothing thrilling about our current political situation, and to be disturbed when - either here or in Spooks - real names, threats and places are deployed in a sensationalist way.

One heart-stopping set-piece featured a Muslim woman, heavily pregnant, riding on the Docklands Light Railway. She was a suicide bomber, her prosthetic belly stuffed with explosives. If I were a pregnant Muslim I would not be grateful to Kosminsky.

His avowed purpose was to explain and understand British Muslim psychology, but in so doing he picked an invented character - the British born female suicide bomber, motivated not by religion but by political anger - and included this commuter scene, chilling yet intellectually irrelevant. The scenes of the bomber in her underwear were shot with a disconcerting tenderness. Making her a female character was a piece of clever directorial calculation, I found myself thinking. When this kind of mental static crackles through viewers' heads, the game is up on the drama.

Other elements in the labyrinthine plot also felt exaggerated, as if they had been included for dramatic purpose. A bright, cheery, secular-leaning Bradford-born Muslim girl is shown being issued with a restrictive control order, which eventually pushes her to suicide. Only 17 control orders have been issued in this country, most to foreign nationals evading deportation. Yet there was nothing in this film that indicated the character's experience was unrepresentative. The uninformed viewer might think it routine, even. This film and others like it are works of invention, yet the fear and mistrust they provoke are real.

It wouldn't be so bad if this drama were not beautifully made. But it was: despite being overlong and studded with self-indulgence, the tension was expertly controlled. There were some good performances, particularly from Riz Ahmed, as the son who joins M15 because he feels a "debt of honour" to Britain. He is also a bit of a cold fish, who gets a girlfriend just for show. Kosminsky was striving so hard to be even-handed, investing the peaceful man with bad characteristics and the violent woman with good ones, that Britz often felt more like a Sudoku puzzle than a human drama.

One thing that can be said for it, though: at least it didn't have it in for any one section of society. It had it in for them all: the police were thuggish, the imam backward, M15 cold, families suffocating. It was generous in its ungenerosity. Britz was Channel 4's 25th birthday gift to the nation. It was always going to include the line "I fucking hate this country"- how far in was the question. Four minutes, as it turned out.

Succour came in the form of The Genius of Photography. Last week's episode, the second in the series, looked at the camera as a political tool. We saw it performing benign manipulation - Dorothea Lange's selective reportage from the Depression, for example: the family depicted in her famous portrait "Migrant Workers" actually had seven members but in editing the group down to four, she created an image that would call more loudly to middle-class Americans. We also saw how in the USSR Alexander Rodchenko created smiles with a scalpel, retouching the faces of a crowd of Gulag prisoners to make it look as if they were cheering Stalin. Later he would perform blunter acts of obliteration, blacking out his sitters' faces. You were left wondering why writer/directors bother making so much up.

Still photographs are cats. They make you come to them. TV is a Labrador, bouncing up to you in a frenzy of sycophantic interaction. Occasionally the differences between the two media made The Genius of Photography feel awkward, with the TV camera escorting your eye around the photographs, zooming in and out like an officious tour guide. Roland Barthes describes how good pictures have a punctum, a detail that pierces the viewer. The pleasure of looking at a photograph is finding its punctum for yourself. Here the TV camera pointed it out immediately, panning urgently out from the wracked hands of the ostensibly calm sitter, say, or closing in on the worn boots by the bed of a New York murder victim. It felt too luxurious to have so much work done for you, and the pace was fractionally too fast to allow due contemplation. More subtitles would also have been useful - many photographs sped by without proper attribution. But these are small gripes; overall it is a series to cherish.

Am I alone in finding Long Way Down more irritating than an out-of-reach mosquito bite? The adventures of Ewan McGregor and Charley Boorman grow ever more self-indulgent in this second series. They seem to think the more puerile they are, the more we'll like them. "I feel like a boy!" crows Ewan McGregor, while his irksome companion makes a joke "using the bomb word" at Gatwick. Do they really deserve a BBC licence-fee sponsored holiday?