Anything goes on television in August. Sitcoms about cancer, blatant hour-long ads for the new Oasis album, even filmed reports by Michael Portillo are considered fair game. No wonder everyone flees to foreign parts.

Portillo it was who provided the week's genuine curiosity. The question of how to dispose of all the Cabinet ministers and gobby backbenchers rendered unemployed by the events of 1 May has yet to be satisfactorily answered, despite the availability of several suitable landfill sites. There are only so many times you can be interviewed by the Daily Telegraph before the days begin to drag and a serious addiction to Ready , Steady, Cook! threatens. Sooner or later ex-politicians were bound to remember that appearing on TV is both more fun and more lucrative than watching it. Indeed, considering Portillo's eye for the main chance, it's amazing it took him so long.

Clever, then, of Leviathan (BBC2, Thur) to employ Central Office's favourite son for the first show of its new run. This modest historical series, a free transfer from Radio 4, would not expect to generate fervent press interest under normal circumstances. Indeed, hidden amongst a wodge of identikit BBC2 factual series, it could conceivably have plied its wares without attracting any attention at all. But the lure of Portillo is hard to resist. Millions who cheered his defeat in the election will have tuned in on Thursday, in the gleeful hope that he would totally muck it up.

He didn't, of course. People don't. But it was a fascinating eight minutes for all that. Portillo's subject, ostensibly, was the political fallout of Sir Robert Peel's repeal of the Corn Laws in the 1840s, and Benjamin Disraeli's patient rebuilding of the Conservative Party in the wilderness years that followed. Sound familiar? Leviathan's brief is to focus on events making the news by examining how history has shaped them, but this was a festival of subtext. "When a political leader makes a new turn, there's gonna be trouble," began Portillo, with a knowing grimace. Sir Robert, he said, was "too aloof to sell his ideas". Disraeli, by contrast, was "a handsome dandy, a ladies' man, fiercely ambitious, deeply in debt, deeply distrusted." By this time the former member for Enfield Southgate was smirking so hard, you feared his head might spin off.

But for all his knowledge of the subject, for all his ability to walk down the staircase at the Carlton Club without tripping up - a missed opportunity there, I felt - a long-term TV career for Portillo looks a distant prospect. Not only did every word spoken seem shaped by his own, very distinctive political agenda, but there was also the far more important matter of his physical presence. Portillo has always had the air of someone who considers himself fantastically good-looking, but here he resembled a demented gargoyle, with a broadcast voice strongly reminiscent of Mr Bean. There is still the all-important role of Tinky Winky in Teletubbies to be filled, of course, but I doubt the handbag is in his colour.

Following a no less distinctive agenda were the makers of Oasis: Right Here, Right Now (BBC1, Wed). Here, at last, was the chance to hear the songs you had already heard 1,000 times on the radio the day before you queued at Our Price to buy the album you'll probably play no more than twice when you realise it isn't actually any good. But this wasn't documentary in the probing, analytical sense of the word, in which you find out things you might reasonably want to know. This was documentary as extended promo video, a sort of audiovisual press release with more spin on it than a Party Political Broadcast. BBC1 called it an exclusive, but a proper commercial channel could well have insisted they pay for the airtime.

So we saw all we had expected to see, and less. The Gallagher brothers being driven around Manchester, pointing out where they used to go shoplifting as boys. Versions of three new songs, one acoustic and played in someone's garden. And interviews, endless interviews with the beetle-browed siblings, each performing his familiar act. Noel modest and unassuming ("We want to blow out every other band into oblivion ... we want to eclipse every other musician in this country"). And Liam blank-eyed and drooling, unable to pass a camera without sticking two fingers up at it. Both agreed that the tabloids had been horrible to them, although by the end of the film I was beginning to feel that they hadn't been horrible enough.

At least the Gallaghers tend to provoke straightforward responses: you either love them or you hate them, and you probably either loved or hated the film about them. But what should we make of Rab C Nesbitt (BBC2, Fri)? When the lead character in a sitcom contracts apparently inoperable cancer and spends two episodes being told that he is about to die, it's hard to extract any straightforward response from the fusion of discomfort, grief, embarrassment, nausea, gut- wrenching fear and total confusion that assails most viewers. We know that Rab isn't going to die, because these are episodes three and four of a six-part series, and writer Ian Pattinson is already working on the next batch. We also know that fatal disease is not one of the easiest subjects to make funny. And cancer being what it is, we also probably know at least one person who is currently dying of the disease, or has just died, or might die. We are terrified to see what barriers of taste will be breached, but we watch anyway.

I'd like to able to say that they got away with it, but I'm not sure they did. Rab's stomach cancer was believable enough, as was his reaction to it - drunken, belligerent and oddly undaunted. Indeed, the illness fitted surprisingly easily into the Nesbitt universe, which is so bleak as it is that the mere notion of certain death can barely affect it. But it wasn't funny. Many of the jokes could be recognised as such. Some, such as Pattinson's attacks on priests, at least let off steam. But I didn't laugh, or smile, or do anything much except feel vaguely uncomfortable. And when Rab was reprieved at the end, just as people never are in real life, I felt annoyed by the sitcomness of it all. It's all very well to break barriers, but they only count if they stay broken.

Death and bereavement are perennially difficult issues for a broad-brush medium like TV to handle, but Hungerford Ten Years On (BBC2, Tues) did an admirable job. Now that we measure our lives by the chronology of disaster, it was probably inevitable that a programme would be made to commemorate the decade since Michael Ryan shot 31 people in and around his home town, killing 16. What wasn't inevitable was that the programme would be so sensitive, dignified and moving. Survivors and relatives all had stories to tell, and some were obviously more bitter than others, but the overriding impression was of a disparate group of people who, by various means, had managed to put their lives back together. The randomness of Ryan's murderous spree may have had something to do with this: there's no pattern in pointless carnage, however hard you try to find one. But let's not underestimate the resilience of the human spirit. Extraordinary events seem to require only ordinary reactions, which is oddly reassuring. In fact, the person who seemed to have coped the least well was the man whose idea it had been to make the film in the first place - a strange irony all of its own.

The single most uplifting moment in the week's television, however, came in the dying seconds of Preston Front (BBC1, Mon) in what the show's fans will no doubt come to know as "the shower scene". For after two and a half series of mute adoration, Carl Rundle finally copped off with the lovely Ally, and we all cheered. This wonderful show continues to be horribly treated by BBC1, which has hidden one of the year's highlights late on Monday nights in midsummer, the scheduling equivalent of being buried in peat. And tomorrow, as the series approaches its climax, it's not even on, the programming demands of the Bank Holiday supersede it. But then anything goes on television in August. Roll on September.

David Aaronovitch returns next week.