Conservative politicians, and their husbands and wives, have always been obsessed with toilets. Last week’s Daily Mail carried a full-page picture of Sarah Vine, partner of the education secretary, Michael Gove, emerging from a “bog standard” public toilet in Westminster, waving an ordinary toilet brush, and declaring that her family will be using public toilets in future, and not the private facilities selected for the ablutions of the families of her husband’s Etonian colleagues.

It’s easy to be cynical about a politician’s spouse using their family to score political points, but finding the original picture of Vine emerging from the Westminster toilet online, before Conservative HQ had cropped it, reveals an image every bit as damaging as that famously suppressed photo of George Osborne poking a proboscis monkey with a pencil.

True, Vine is holding an apparently ordinary toilet brush, of the sort ordinary people like the late Jade Goody or that woman who put the cat in the bin might use, but zoom in on it and it appears that the handle is made from the ivory of the severely endangered African forest elephant, which sells at a million pounds an ounce, while the bristles have been fashioned from the tail hairs of the virtually extinct white rhino. Is this the sort of toilet brush that would wave in the hand of, for example, ordinary folk like Jimmy Pursey from Sham 69 or rap’s Dizzy Rascal?

Meanwhile, the tiny brown flecks on Vine’s toilet brush are revealed not to be the excrement of ordinary people, like Ray Winstone or Dappy, but tiny flakes of Green and Black’s organic Maya Gold dark chocolate, the most expensive chocolate in the world. And the transparent sheet of toilet paper flapping from it is not the tracing paper type we might see wiping the bottoms of working-class heroes like White Dee or the late Bob Crow, but is in fact a gossamer-thin whisper of silk, provided by the top people’s department store, Peter Jones of Sloane Square, official silk supplier to Michael Gove’s family’s bottoms.

View the picture in full, and Vine is not emerging from a “bog standard” public toilet at all, but from the marble edifice of Green Ernie’s Church of England Toilet for Girls in Westminster, one of the least socially inclusive toilets in England. While the toilet is nominally open to the public, the majority of its customers are given keys on religious grounds, and a quarter on their ability to work the hand-dryers properly, and when you have factored in the exclusivity of its location and the wealth one would need to move into its economically cleansed catchment area today, the political exploitation of Vine’s egalitarian toilet choice begins to look crass. What would Jesus do? It’s impossible to say, but like the new pope, he would probably have chosen the tracing paper toilet tissue on purpose.

That said, it is difficult to criticise anyone for the choices they make where their family’s toilets are concerned. The Free Toilets Movement, championed by the BBC TV personality Toby Young, aimed to liberate toilets from the interference of the state, allowing toilet users to make their own choices as regards soap brands, toilet paper texture, and whether the graffiti should be in Latin, like in Pompeii. In setting up the pioneering Hammersmith Free Toilet, Young won hearts and minds by explaining there was no guarantee that, once his new experimental toilet was built, his own family would even be allowed to use it. But then, just at the last minute, the rules changed and they were.

(In the interests of full disclosure, I must admit that I made enthusiastic use of fee-paying private toilet facilities during my teens, having been granted access to them via a bursary for “waifs and strays”, and as a result of scoring highly in a test of my abilities to drown flies while using the boys’ urinal trough. In the further interests of further full disclosure, I should also admit that I was privately tutored in this skill, during a family holiday in Malta in the mid-70s, by my grandfather, who had been a gunner in the RAF in the second world war.)

While it’s difficult to censure Vine for making use of a system that was open to her, it’s harder to accommodate the exploitation of that choice, of that cultural and geographical privilege, for political ends. The ginger tomcat from down the road came in through our cat-flap last night and defecated, twice, in the kitchen. It appears to have the same electronic cat-flap collar key as our cat, and so has unlimited access to the house. I saw the first piece of cat excrement, by the radiator, at about 8am this morning while giving the children their porridge. I cleaned it up, mopped the floor with disinfectant, and washed both of my hands, then slapped them together three or four times and shook them out twice, the international Oliver Hardy gesture for having completed an unpleasant task.

Later on, my wife, having seen the second piece of cat excrement, by the window, which I hadn’t noticed, accused me of deliberately ignoring it. She said I had left it for her to remove, having misunderstood that when the three-year-old told her that Daddy had “seen the cat poo”, she was referring to the first piece of cat excrement, which I had already dealt with. It was not even nine o’clock and already our day had descended into the usual accusation and counter-accusation.

But I bear the ginger cat that defecated in our kitchen no ill will. It did nothing wrong. There is no active moral dimension to the cat’s choice of toilet location. Finding itself in our house, in an increasingly gentrified part of Hackney where less well-off cats will soon be a rarity, it merely took advantage of the best toilet facilities available to it. The cat is without blame. What would have annoyed me would have been if the cat had then written a thousand-word piece for the Daily Mail implying that the lovely kitchen it was privileged enough to be allowed to defecate in, by virtue of the accident of its postcode and its electronic collar access key, made it in some way morally superior to other cats.

Stewart Lee appears, in a performance of John Cage’s Indeterminacy, as part of the Usurp Chance tour at Birmingham’s CBSO Centre on Tuesday. Stewart Lee’s Comedy Vehicle is on BBC2 on Saturdays at 10pm, except in Wales, where it appears randomly