‘At times you can almost sense relief that lots of Those Sorts of People are now judged to have been offloaded to Ukip.’ Illustration by Jean Jullien

In reality – as opposed to reality television – there is no need for an explanation. Photo of a house strung with two St George flags (one covering a window) and a West Ham one? The reason the Twitter storm whipped up with such lightning speed – even by the medium’s own disingenuously outraged standards – was because people thought they knew what Ms Thornberry meant.

And by knowing what she meant so instinctively quickly, they surely betrayed themselves too. They recognised the contempt so swiftly for reasons they did not care to admit – or at least, not in the open. In that spellbinding speech from A Few Good Men about people being unable to handle the truth, Jack Nicholson has contempt for stagey idealism – for people saying one thing, and thinking another “ deep down, in the places you don’t talk about at parties”.

Deep down, in the places they don’t talk about at parties, they knew exactly what Thornberry meant by her picture. She was stupid enough to reveal it, of course, which means she’s in entirely the wrong game, but most of them would have fancied knocking on that door about as much as she clearly did.

And if Ed Miliband really had never been so angry as he was with Thornberry– as all his team’s briefings have taken such huge pains to insist – then I expect the Labour leader knew even more keenly than many what she meant. People have a tendency to bridle most angrily when a nerve is touched; when a voice is given to a corner of their psyche over which they know it’s more politic to draw a veil. At those points, attack seems the best form of defence. But it isn’t, as I suspect Miliband will find out now he’s given this an extra set of legs by in effect sacking her.

Still, like everyone else who piled in, he saw that a picture needn’t be worth a thousand words when three will do – People Like Them. And People Like Them are the most unknowable tribe in politics these days.

Labour’s excruciatingly self-loathing attempt to humanely out-Ukip Ukip, Cameron’s serial distaste for his own core vote … isn’t it just all desperately “People Like Them”? Deep down, in places they don’t talk about at parties, both sets of top brass wish to God they didn’t have to suck up to Them, and at times you can almost sense relief that lots of Those Sorts of People are now judged to have been offloaded to Ukip.

They haven’t necessarily been, as the occupant of the tweeted Rochester house shows. At the time of writing, Dan Ware’s tweets had yet to be discovered. (Gosh, he may not even be on Twitter, if you can imagine such a thing. Luckily, lots of people in London are on it for him.) But going by what he told the Sun, his contempt is reserved for the entire political class. “No matter who you have in, it doesn’t matter,” he declared. “I can’t remember the last time I voted.”

The Sun’s contempt, meanwhile, purports to be entirely for Labour. Voters suspect, the paper’s leader column informs those same voters, that Miliband’s lot “secretly hold their values in contempt”. I’m afraid that I shrieked with laughter at this, having a terrible weakness for the Sun’s attempts to convince its readers that it holds them in total reverence.

I’ve worked on two tabloids (one of which was the Sun), and sat in on numerous editorial conferences where “meet the readers” was shorthand for being sent somewhere that you really didn’t wish to go. I remember one discussion about an interview that someone had done with a reader. “What was the house like?” the editor sniggered with a grimace. “Don’t tell me – sticky carpet. Did you wipe your feet on the way out?”

Still, back to the Sun’s leader, which explained: “Those who run Labour never sully themselves by getting to know any ordinary people. They are confused and repulsed by them.” A piece of common touchery which somehow calls to mind the practice of the former Sun editor Rebekah Brooks of holding executive awaydays at the holiday camps to which the paper sent its readers on £10 promotions. The events were viewed with dread, with senior staff ordered to immerse themselves in their surroundings, as though they were places of positively Martian otherness.

It’s a culture neatly satirised in Martin Amis’s novel Yellow Dog, where readers of the Morning Lark tabloid are referred to at all times as wankers. “Our target wanker’s the unemployed,” staff are informed. A drop in circulation indicates the paper has “lost wankers”.

But if a Martin Amis reference is too wanky, for want of a better word, then consider a piece of email evidence produced this week in the trial of a senior Sun reporter. He sought to assess the credibility of a police source by asking him to provide titbits of information that would never be known by “a pleb who’s read the papers”.

Of course, you’d have to think that this sort of thing can’t possibly be limited to tabloids. I expect there are Guardian journalists who’d lump their online “community” together as one homogeneous entity that they hold in something other than esteem. Off the record, naturally.

Such a lot of contempt swilling around our politics, all told, and only Mr Ware able to voice his out loud without giving a toss. Where else would his contempt take him, were the tape recorder left running? In the coming days, people will try to find out – people on the left, mostly, because then they will be able to harness his contempt and deploy it in contempt for those said to be pandering to the contemptible.

As for where all this back-and-forth will leave People Like Them, the answer would seem to be: swollen in ranks. In fact, their numbers seem to be mushrooming so uncontrollably that at this rate, it won’t be long before People Like Them are the biggest demographic in British politics.