Successful adverts always tell you a "fundamental truth" about the product: whatever a VW Golf advert says, it always reminds you they're reliable.

It got me thinking how politicians only fall when their "fundamental truth" vanishes.

Thread

A PM can abandon every principle, but still succeed if their "fundamental truth" remains needed.

Thatcher was cruel but effective. Love or loathe her, she got the job done. Her "fundamental truth" was: competence.

She failed as a PM when we lost trust in that competence.

Major's "fundamental truth" was admin. He wasn't sold as dogmatic or cruel, just a dull accountant you could trust, and basically ignore while he did boring stuff for us.

He presided over countless scandals, but only failed as a PM because his accountancy skills failed.

Blair's "fundamental truth" was a hopeful future and rebuilding society. He failed as a PM when he cynically destroyed one instead.

Brown's "truth" was economic competence, and he fell apart when that went.

And so on.

Each PM survived countless errors and scandals, as long as the fundamental thing we originally "bought" remained.

We will accept a VW being a bit dull, costing too much, having few standard features... but if it breaks down, that's when we feel betrayed.

Boris Johnson's "fundamental truth" was that he's a fun guy who would break things.

His voters were sick of nerdy people sticking to awkward rules they never wanted to learn about. Johnson promised to smash, and giggle. Irresponsibility was his "truth".

But that "truth" doesn't fit the world now. We don't want to laugh. And things are breaking way too all on their own; so we need somebody serious, who will fix things.

But no matter what, he fundamentally is not that guy. And that fact will destroy him. Quite suddenly.

Cos that's the thing. When your VW breaks down, why throw more money at it? Have you seen the price of fixing them? Forget it. You want a new car. Tomorrow.

When Thatcher's "truth" vanished, she was gone fast. Brown too. Major. May. When the time comes, it's done in a flash.

The world is full of people confidently predicting X leader will go in Y months. I'm not doing that.

But Johnson is the wrong man with the wrong skills. And irresistibly, that truth will grow in people's minds.

And there's not a thing he can do to stop it.

If he was wise, he would buckle down and do mountains of homework. He'd stop all off-the-cuff speeches and linguistic flourishes. He'd impersonate Brown or Thatcher: a serious person or a driven one.

But he can't. It's not him. We wouldn't buy it if he tried.

I find it interesting that his opinion poll ratings used to rise when he made public appearances and dip when he was away from the camera.

Now it's the reverse.

Cos his fundamental truth is not what the country wants now.

And that will finish him off.

/end