Say what you like about Jeremy Corbyn, but he's a man of principle. That's the party line, isn't it? Useless he may be. Bearded, too. But by golly, beneath that bushy exterior beats the heart of an honest man – a man of parts, a man of the people, a man quite unlike the Tory toffs and Blairite traitors who so often squirm and worm their way to the top of the greasy pole.

Why, here he is, pictured on the Guardian website – that paragon of decent journalism – forced to sit of the floor of a Virgin train because it was so, in his words, "ram-packed". Other politicians might have demanded a free upgrade to first class, but not our Jeremy. No sir. He preferred to sit on the floor, like the unprivileged, ordinary bloke he is. Accompanied, quite coincidentally, by a camera crew.

An impressive display of humility, no? Proof that he really is unlike other politicians?

Hardly. As the world now knows, the whole thing was a grubby little stunt, a put-up job designed to publicise his policy of renationalising the railways. There were plenty of seats on that particular train. The Labour leader simply ignored them as he walked past. So, naturally, he is now inundated by the sneers and the jeers of his enemies – most of them in the Labour Party – as they queue up to denounce his hypocrisy.

Well, Mr Corbyn's reputation for honesty is certainly dented. Moreover, his uselessness as a political leader is confirmed, since his antics have served only to divert attention from Virgin's many faults and the real problems arising from a botched rail privatisation. He deserves all the stick he is getting.

Jeremy Corbyn Virgin Trains
Jeremy Corbyn sat on the floor of the Virgin Train to Newcastle on 11 August Keren Harrison

But is he really so much worse than other politicians, here and around the world? I wonder.

Just look at his rival for the Labour leadership, Owen Smith. He certainly seems a better bet than Jeremy. He shaves. He wears suits. And he has the backing of such party 'heavyweights', if that's the right term, as Ed Miliband. But the moment he opens his mouth, he gives the game away.

Who would have thought that the party of Clement Attlee could sink to this?

This is a would-be leader who tells us that he wouldn't lead at all. Instead, he gutlessly sucks up to the hard Left by promising to take orders from the Labour Party conference, a body famed for the barminess of its decisions. What's more he suggests that we should negotiate with Islamic State (Isis), apparently unaware that these psychopaths have no policy other than the destruction of Western democracy and the establishment of an Islamo-fascist caliphate. Not much scope for negotiation there, Owen.

Not that previous Labour leaders were especially impressive. Gordon Brown's control-freakery and titanic rages led some of his closest associates to suspect that he was unhinged. As for Tony Blair, the least said the better. All those election successes can't conceal a record in government, from Iraq to immigration, that looks tawdrier by the day. Who would have thought that the party of Clement Attlee could sink to this?

And what of the other side of the political fence? David Cameron certainly achieved some success in making the Tories electable again, and always seemed comfortable as Prime Minister. But let's not forget that he's just as capable of gross hypocrisy as Corbyn.

After becoming Tory leader he made great play of his green credentials, ostentatiously cycling to work to demonstrate his devotion to the cause of low-carbon transport. But that was a stunt, too. In 2006, we discovered that Cameron was followed on every one of his 'green' bike rides by a taxpayer-funded, chauffeur-driven limousine carrying his papers and office clothes.

Well, at least he was a pretty competent PM, wasn't he? A far better leader that Corbyn could ever hope to be? Perhaps. But he also opened the door to political censorship of the press with his panicky response to the phone-hacking scandal. He forgot the lessons of Iraq by bombing Libya, scuttling away after the fall of Gaddafi and leaving a failed and ruined state behind. And he made a complete Horlicks of the EU referendum campaign.

We can only cross our fingers and hope that Hillary wins, though it is the greatest of pities that both can't lose

So where can we look for real political leadership? Not to France, where the hapless, hopeless President Hollande plumbs new depths of unpopularity. Not to Germany, where the previously unassailable Angela Merkel is struggling to cope with the consequences of her 'come one, come all' immigration policy. And certainly not to a third-rate EU Commission under the egregious Jean-Claude Juncker.

Nor is there much inspiration to be had in the land of the brave and the home of the free. The real mystery is how a United States that can boast such spectacular talent and such brilliant achievements could possibly end up with a a Presidential contest between Donald Trump and Hillary Clinton. Heaven help us, we can only cross our fingers and hope that Hillary wins, though it is the greatest of pities that both can't lose.

The good news for Jeremy Corbyn in all this is that uselessness is not necessarily a barrier to political success. Look, he has a better hairstyle that Donald Trump. He doesn't drink as much as Jean-Claude Juncker. He hasn't been caught on illicit midnight assignations like Francois Hollande. He's not nearly as shifty as Hillary Clinton. In fact, compared with some of them, doesn't he begin to seem quite plausible?

Michael Toner is a former Fleet Street political editor and co-author of a series of Bluffers' Guides on Europe.