Stewart Lee. Illustration: David Foldvari

In my shabby north London arts/media ghetto, one is never more than 6ft from a rat or six degrees of separation from a New Labour politician. Only last month, I saw shadow chancellor Ed Balls fingering a homity pie at the farmers' market. Some friends are even acquaintances of opposition bigwigs. And some of them can't keep secrets.

Because my wife is a feminist, (though typically unable to return my CDs to the correct genre, chronological and alphabetical position on the shelves when she brings them in from the car), I do some of the childcare. Being the only dad at Messy Play, a spy in the cab of gender, I realise men's conversations are status-securing exchanges of valuable facts, whereas women's are a two-way ebb and flow of non-assertive opinion, emotional support and bitchy gossip.

"June's friend's friend, the New Labour guy, is having terrible trouble with his plumbing?" "Erectile dysfunction?" "No," said Pauline, "a problem with his actual plumbing. They had to get a man last month because for about five days there was a number two that just wouldn't flush away. It wasn't especially big but what was weird was it looked like Tony Blair." The mums shrieked with laughter. "What do you mean, it looked like Tony Blair?" I asked, smelling a story. "Did it look like the whole of him, with arms and legs, or just his face?" "Just his face, I think," said Pauline. "I don't really know. I'm not supposed to say anything. Apparently the spin guys are really worried about the story getting out."

The next day, I myself had to call a plumber. I had accidentally put cat litter crystals into the dishwasher salt compartment and they needed to be sucked out by a professional. I don't know anything about sport so I volunteered: "Hey. Apparently there's a New Labour politician round here and last month he had to call a plumber because there was a turd with the face of Tony Blair that he couldn't flush away." "Walls have ears," the plumber laughed, adjusting his turban. "That was one of my call-outs. It was really like Tony Blair too." "In what way?" I asked. "That's the funny thing," the plumber said. "It didn't really look like him, but it just was really like him. It was obviously him. It seemed evil. And it was smiling. And no one in the family could remember having done it."

For a few minutes, the plumber sat in silence, staring, fondling his tools, puzzled by the memory, at £80 an hour plus call-out. "Whoever told you got one thing wrong though," he said, snapping out if it. "It wasn't last month. It was yesterday. And it wasn't a he. It was a woman politician. And she told me not to tell anyone about it. So if you wouldn't mind… that'll be £400 please."

Either Pauline was mistaken, and had mixed up the gender of the politicians, or there were two different north London New Labour politicians plagued by persistent voting floaters. And how could Pauline have told me a story last week that the plumber said only happened yesterday? Maybe there were two "Tonys"? Or maybe only one, but it was using the sewer system as a kind of personal transport network between the toilets of former minions. Or the whole thing was nonsense.

After lunch, I saw Diane Abbott, our local New Labour MP, with whom I am on nodding terms having been on Andrew Neil's BBC2 politics show with her three times, in the post office. Intrigued by the toilet tale, I decided to chance my arm. "Have you heard about this poo that looks like Blair?" I laughed. She gripped me tightly by the wrist and dragged me away.

Sitting out of sight, spy style, on a bench in the park, which has recently been beautifully refurbished, Abbott was fearful and nervous, but masked it with a bristling anger. "Who told you about this? The damn thing only appeared this morning. My cleaner is at home spraying it with Febreze and hitting it with the toilet brush but it keeps resurfacing. You'd better not tell anyone. This is a bloody PR disaster waiting to happen. I suppose you bloody know about all the others too? You know about Ed's problem?"

"Ed Balls?" I offered, having assumed the Blair poo Pauline had mentioned at Messy Play was plaguing the toilet of the shadow chancellor, who lives locally. "No. Balls's problem is small time. Ed Miliband." I could see Diane Abbott was torn. On the one hand, she knew she shouldn't be telling me, a standup comedian with an occasional Observer column, about Ed Miliband's plumbing problems, but she was clearly desperate to unburden herself.

"Ed Miliband's personal House of Commons toilet has been home to a persistent floater with the face of Tony Blair for six weeks now." "Can't they just flush it away?" I asked. "That's the problem. Ed flushes it away, dozens of times a day, and it just keeps coming back. In the end, he got John Prescott to go in and do a big massive fast wee on it, smashing it all to bits, and they flushed the fragments away, but then they just seemed to re-form and it came back, looking even more like Tony Blair than before."

"Don't worry, Diane. It will be all right," I said. "No. It won't be all right," she shouted. "The toilets of dozens of senior New Labour MPs all over the country are being regularly infested by a poo with the face of Tony Blair that just won't flush away. What's going on? And if this gets out… it's a gift to the Tories. It's like a joke, a bad joke, some heavy-handed routine about Blair coming back, smiling and… don't you dare write this up in one of your columns."

"You don't have to worry, Diane," I assured her. "I hardly think the Observer would stoop so low as to run a full-page column on some poo with the face of Tony Blair. People would assume the story wasn't true and just think it was the most pathetic, puerile, pointless piece of so-called satire ever run in a British broadsheet newspaper." Then her phone rang. "Pavlika. No, Pavlika. Hit it. Hit the bloody thing with a broom. Smash it to fucking pieces."