Declining standards are visible everywhere in Britain these days. But the recent fiasco over MPs expenses claims is, sadly, grist to the mill of all those who have likened Britain's supposedly fine and upstanding MPs to pigs in the trough. And whenever there's a pig in the trough you always find one of those irresistible swoops into convoluted English designed to put listeners off the stench.

At the helm of this charade is Speaker Martin, a magnificently inflated self-righteous puffball with a haggis on his shoulder. This man has done more to lower the standard of parliament in people's eyes than any other speaker. But even political satirists and sketch writers couldn't do justice to Speaker Martin's contrived excuse for his own avarice. "I didn't come in to parliament not to take what's owed to me," he apparently told an MP.

Well, what is "owed" to him? Let's see, he has a grace-and-favour home and a chauffeur-driven car. He has also managed to claim more than 50 000 pounds in air travel costs. And Mrs Martin has apparently also run up a 4000-pound taxi bill doing the household shopping.

But it is not really my purpose here to examine Speaker Martin's extravagances. The key point is this: Speaker Martin used a double negative. And whenever someone resorts to a double negative, particularly when the person in question is not usually intellectually equipped to so do, you know something's up. Basically, call Columbo, Hercule Poirot and Inspector Morse  – this is legerdemain and manipulation on a grand scale.

I'll never forget Enoch Powell's intriguing self-justification before his so called Rivers of Blood speech. Anticipating perhaps the wave of revulsion expressed by liberal opinion before his discourse on immigration on April 20 1968, Powell issued a disclaimer. "How dare I say such a horrible thing? How dare I stir up trouble and inflame feelings by repeating such a conversation? THE ANSWER IS I DO NOT HAVE THE RIGHT NOT TO DO SO."

Marvellous! I don't mean to compare Speaker Martin to Powell. That would be like comparing Gordon Brown to Winston Churchill but I cite Powell only to point out that when you know you're in in some trouble (or in Powell's case about to stir the pot – big time) there's nothing like the seductive lure of a labyrinthine double negative.

First, people who are inclined to respect the speaker's status may be intimidated by this turn of phrase - or at least the unskilled listener may have to mull over the answer for –  say –  15 to 20 seconds before appraising its worth. It is designed to confuse the uninitiated. By then, of course, Speaker Martin will hope to have fobbed off his listener and will have moved on to something else.

Second, it creates the impression that Martin is a decent and principled man. Note the honourable-sounding beginning..."I didn't come into politics..." This is a particularly deceptive turn of phrase because it creates instant expectations. Most people hearing this would assume that Martin was about to reveal an altruistic intent, a sincere justification for his chosen career path. Normally, it would be reasonable to expect such a person to continue along these lines. "I didn't come in to politics to see the image of the House of commons demeaned" or "I didn't come into politics to see my constituents' rights trampled on". But Speaker Martin has a wholly original take on this. "I didn't come into politics not to take what's owed to me".

Ok, it doesn't really take Hercule Hershman to unravel what Martin is really saying. Basically, that's right: "I came into politics to take what's owed to me", in other words – to stuff himself with as many perks and riches as he can get his hands on during his time at the top. To ensure that his corpulent body grows ever more corpulent. But, needless to say, he couldn't say that. So he skilfully inserted the negatives. Nice one. Still, it has to be pointed out.

After all, I didn't enter journalism not to identify a greedy, self-righteous jumped up Johnny of a Speaker when I see one.