If I had seen Louis when he "met the Hamiltons", before I agreed to his making a documentary about me, I would not have touched the project with a ten-foot bargepole. But instead, I saw his programme on Paul and Debbie Daniels, which appeared perfectly sensible, tracing the ill-fated attempt to set up the Ballet Imaginaire.
There is always a risk in this sort of programme, an awareness that the programme-maker may need something unusual, dramatic, scurrilous or ludicrous to make any sort of reputation in the media climate of today. A fly-on-the wall documentary carries those risks in spades. The cameras are there throughout the day. If you trip over a pebble, yawn indiscreetly, scratch yourself, drop the crockery, fail to answer a question from a primary school pupil or forget someone's name at a vital moment, the event will be captured and replayed to make you an object of ridicule evermore. All that posterity will remember of Dan Quayle is that he can't spell the word potato.
I think I have avoided those particular traps, but there are plenty of others. I have always turned down Have I Got News For You on the basis that I am not quick-witted enough to beat the regulars (and even if I were, that wonderful moment would no doubt be edited out). I once accepted Clive Anderson's show against official advice and was glad I did, because it worked well. However, I let Simon Sebag Montefiore film me for a day and will never give him another millisecond in the future. I have turned down Ruby Wax and the harmless Kumars at Number 42 because I did not believe I would be comfortable with the style.
Louis Theroux's intentions may be honourable, but his style is a combination of the fast-bowling Have I Got News For You, the frivolity of Sebag Montefiore, the inquisitiveness of Ruby Wax and the innocent silliness of the Kumars. On top of all that, he affects a naivety that can sometimes catch his subject unawares. He can, however, overplay his hand, as he did when trying to convince me that he, who had read history at Oxford, did not know whether St James's Palace was still standing.
On another occasion, as we approached the House of Commons, he called out to me to ask why the crew were filming me. The answer, of course, was that they were filming him filming me, and he knew that. I refused to spell it out and instead called back: "Oh, there's a leadership election on."
Above all, he is curious. Could he film my bedroom? No. Why not? Because it's private. Why? Because most people have private and public rooms in their houses and I am not an exception. Could he film the bathroom? No. Why not? Because I do not believe the nation is remotely interested in my loo. But your bedroom looks perfectly normal (as he peered in through my bungalow window). It is, but you still can't film it and I am going to stand here to make sure that you do not. Why?
I let him and his camerawoman, Kate, spend two days with me as I took a fortnight's holiday on a cruise ship. Could they film me swimming? No. Why not? I did not wish to be filmed in my swimming costume. Not even Theroux could ask "Why?" to that.
Theroux also wanted to film me with my friends, and reactions predictably varied. "I do not want to be on television at all," insisted one friend. "But why didn't you bring him round for a drink?" wailed another.
Then there was family. Ever since my mother has come to live with me, I have guarded her privacy with the fierceness of Cerberus at the gates of hell, and have done so at her own request. So I limited Louis to one interview and the poor soul would flee upstairs every time he came inside my London home. I often wondered if the crew thought the whine of the stairlift was an echo of the doorbell, so regularly did the one follow the other.
Contrary to popular imagination, a fly on the wall is not there all the time, or you would swat it in pure frustration. Filming took place over several months but days would go by in between shoots. Even so, by the end of the documentary, I was worn out with it all. So were my staff, who rebelled against any further intrusion into a busy office.
During the documentary, I became aware of a very simple fact, one that I had never previously appreciated sufficiently: you choose your friends for their conversation. Not just for their character, their loyalty or likeability, but crucially for the ease with which you converse with them. Louis Theroux is likeable and charming, but unless you enjoy a perpetual inquisition (he spent five whole minutes examining a throwaway remark that I don't like the modern custom of holding discos after weddings), or the deepest analysis of every preference or personal trait, he is an exhausting companion. The difference between a duel with Jeremy Paxman and one with Theroux is that Paxman is serious and short on time, while Theroux is (or at least pretends to be ) frivolous and long on time.
However long the making of a documentary, it has to be cut down to an hour or less of viewing. Inevitably that produces the odd distortion, but, to Theroux's credit, there was only one reply where I felt the brevity destroyed the real case I was making. Asked several times in the course of filming why I thought fellow MPs had been so reluctant to countenance me as party leader, I gave a host of reasons: my views on morality and fox-hunting, my political style, my odd looks, my traditionalism, the drugs debacle, etc, etc. In the end, all he showed was a one-line comment that my colleagues preferred a pinstriped male. I blamed myself for giving him something that could be isolated as a one-liner.
We ended with a trip to London Zoo, where I cuddled a lemur and everyone said: "Ahhh! Isn't it sweet?" The programme didn't show that, either. I suppose I should be thankful it didn't end with a circus.
Why did I agree to do it? Am I glad or sorry? Would I do it again? I did it because I liked the Paul Daniels documentary and would always say yes to a genuine programme unless there was a good enough reason to say no. I reserved judgement on whether I was glad or sorry to have done it until I had had a chance to gauge reaction. All my correspondence and e-mails were favourable, while press comment was, predictably, mixed. Some journalists were clearly disappointed that Theroux had not made a complete fool of me, while others had enjoyed the duel.
Would I do another fly-on-the-wall? I can only give the same answer as I do when asked if I would ever return to the front bench: "If I do, it will not be for some time - I need a chance to breathe."
Ann Widdecombe is Conservative MP for Maidstone and The Weald