If you or I were a reformed pin-up of the Tory right, would we have agreed to star in a documentary about the famous anti-Semite and Hitlerian fixation, Richard Wagner? Only, perhaps, if we had ruled out all hopes of an electoral comeback. If I learnt nothing else from the first episode of BBC2's Art That Shook the World (13 July) - and, actually, I learnt quite a bit - I did glean that Michael Portillo's political career truly is over. No one who intended to lead a party into a future election would have handed fortune so many visual hostages. Not since George Brown was persuaded to sing "My Way" on television - a moment preserved in Alan Yentob's Arena documentary on the song - has a politician so set himself up, or been set up, for archival ridicule.
Exploring the theme of power in the Ring Cycle, Portillo was filmed strutting about the ramparts of a Bavarian Valhalla, in a ring of fire; alone on the balcony of the Bayreuth Opera House, as archive film flickered of Hitler coming up the drive; and on the conductor's podium in the concert hall itself: "I have the orchestra laid out at my feet. I have total domination. I have never felt so powerful in my life."
This is as near as you'll get to Portillo saying "I'm a power-crazed monster", although, because he is still in his mea culpa phase, we were meant to understand the coda: "But I'm all right now." Wagner, he explained, had written a series of operas about the terrible price in lost love paid by people who do anything for power. "As someone who has been in politics for 25 years, I've seen it all and understand what Wagner means," he said. He meant himself.
"It is addictive and very enjoyable, actually," he told "psychiatrist and Wagner fan" Sheilagh Davies. "I think it can be corrupting. It removes you from the real world and can make you insensitive." The shrink sat at the head of a couch on which Portillo, instead of lying on his back and looking away, crouched as if about to pounce, a great beast filled with dangerous charm. Arms folded defensively, she looked terrified, as Portillo proceeded to analyse himself in Wagnerian terms. "I no longer have power, so that means there's time for love," he concluded, a chat-up line we all might want to squirrel away for a rainy day.
Within the hilarious scheme of Portillo as tragic hero, however, thrived a perfectly good documentary about the technique of the Ring Cycle, a concise and irreverent biography of Wagner, and a reasonably successful attempt to explain why it has the power to induce both love and hate. A tame rabbi suggested that, never mind the plot, the music subliminally relayed Wagner's anti-Semitism, soul to soul. The only thought left unsaid was that there must be millions of Wagner fans who, like me, find the music powerful, but the plot enjoyably absurd - as likely to leave the opera wanting to invade Poland, Woody Allen quipped, as we are to sign up to become Jedi knights after watching Star Wars.
The show gave me an excuse to watch a recent Artsworld documentary, Wagner's Ring Cycle, which I had recorded in May, but not got round to watching. Presented by Richard Coles and made last year by Illuminata Films, it covered much the same ground, had a budget sufficient to get itself to Bayreuth, was beautifully filmed - and even interviewed one of Portillo's talking heads, the great British Wagner bass, John Tomlinson, and to better effect.
Either programme would have whetted an appetite for the operas, but Portillo's would also have amused a separate constituency: those intrigued by the politician himself. Others, I dare say, would have avoided it for that reason. Personally, I like opinionated documentaries and greet the rumours that Alan Yentob is to take on the Melvyn Bragg-role for a new BBC1 strand of mainstream arts programming as good news, equivalent to David Attenborough leaving his executive's office and going back to film-making.
Could Artsworld, I wonder, have been saved if Jeremy Isaacs had sat in an armchair and welcomed us to his digital channel in the way Alistair Cooke used to introduce Masterpiece Theatre in America? Would Rosie Millard propped against the bar in Soho House have done it better? Whatever: a lack of personality, of front, or of identity contributed to the channel's recent sad collapse, despite the excellence of many of its programmes. Another blow was the launch of BBC4 although, ironically, its dedication to the arts is set to weaken under the BBC's new director of television Jana Bennett, who is sceptical of niche channels.
The strange fact, in any case, was that the wholly commercial Artsworld was upmarket of BBC4, which will show Portillo on Wagner for ever, but it is unlikely to transmit a complete Ring Cycle as Artsworld did twice. Shame on those who did not subscribe and on me for not reviewing it enough. Shame, too, on the Arts Council for missing a chance to back a dirt-cheap way of getting art to the people. One tip: on Sky Channel 464, there's something called D-Classics TV, which shows opera, concerts and classical theatre free to air every night. It's not Artsworld, but it's something - and the chances of its being able to afford Michael Portillo as an anchorman are negligible.
Andrew Billen is a staff writer on the Times