Sinn Fein is panicking as its brothers wreak havoc in Greece

She taught what we would now describe as 'challenging' children, one of whom was a boy who had set his face against learning to read, on the grounds that it was unnecessary to the job he wanted as a labourer on building sites. Patiently, she explained to him that even in these circumstances, reading could be a vital skill. "For instance," she said, "think what would happen if you went into a building on the site without being able to read the warning notice saying: 'Explosives.'"

He became quite cross. "It wouldn't matter," he shouted. "If them explosives went off I'd kick them and bate them."

That's just about what Tsipras and his cheerleaders thought would work with the combined forces of the EU, the ECB and the IMF.

It hasn't.

It's also what Sinn Fein insists will work with the British government. In a particularly risible episode, at an anti-austerity protest in Trafalgar Square last month to which few MPs turned up - where the stars were the comedian Russell Brand and the singer Charlotte Church - Martin McGuinness, a member of a supporting cast, told the crowds: "I bring solidarity from Ireland and from all of us fighting right-wing Thatcherite policies on both sides of the Irish sea."

Er, Martin, sometimes you show your age. That may be a rallying cry for the over-fifties, but Thatcher lost power 25 years ago and means very little to the young. Shouting, "we will not be cowed, threatened, bullied or bribed", McGuinness was denouncing the "welfare cuts" (left-wing terminology for welfare reform) without which the North's public services will go bust and the Executive will fall.

Unfortunately, as Theresa Villiers, Secretary of State for Northern Ireland, put it: "Northern Ireland cannot be immune from the kind of decisions that have had to be taken by responsible governments across the developed world over the last seven years since the crisis hit." Its leaders, she added, had a clear choice. They could implement the Stormont House Agreement (in which they and the DUP agreed on welfare reform) "and tackle the hard choices of responsible government . . . or they can go down a path of reckless irresponsibility that leads to the kind of politics now playing out in parts of Europe."

But then as Leo Varadkar - who, like Villiers, is part of a government that has had to implement a policy of financial prudence - put it last week apropos Greece, "It seems like the student union has taken over the government."

What all those left-wing movements seem to share is a belief that somewhere there are hidden piles of money that will enable them to behave towards their constituents as Bertie Ahern did in the good old days. Their fantasy world is one of manna and golden eggs, but they've never absorbed the morals of the stories. Yes, Jehovah kindly distributed manna when the Israelites were starving in the desert, but having given them twice as much on Saturday to get them through the Sabbath, he was livid when some of them scoffed the lot and then demanded a delivery on Sunday. And he stopped giving when they got out of the desert.

You could read that as a morality tale about welfare dependency.

Yes, the goose laid golden eggs, but when the farmer killed it because he mistakenly thought it contained a huge lump of gold, the eggs stopped. A fable about bleeding capitalism dry, perhaps?

The far-Left might also bear in mind the parable of the good Samaritan who helped the injured man ignored by others. As Mrs Thatcher put it crisply: "No-one would remember the Good Samaritan if he'd only had good intentions; he had money as well."

But, of course, reality is not easily embraced by the inhabitants of the international room of the students' union, aka the European grouping GUE/INGL (the European United Left/Nordic Green Left). They talk each other up, appear at each others' conferences and pass mutually supportive motions. Telling Sinn Fein's An Phoblacht that his heroes were Karl Marx and Che Guevara, Varoufakis - the coolest kid in the room - was eloquent about his long-time interest in Ireland; he was a member of the Troops Out movement and a singer of Irish rebel songs.

Only last week Pablo Iglesias, the leader of Podemos, told The Times of London that when it comes to the United Kingdom he's on the side of the Scottish National Party and Sinn Fein: "For me the fundamental element has to do with the defence of social rights, as with Sinn Fein, defending the rights of the working class."

As far as I'm concerned, the Greeks would be doing themselves and everyone else a favour if they negotiated a soft exit from the euro and helped precipitate the break-up of one of the stupidest initiatives of the EU elite. But - like Sinn Fein - Syriza have insisted that it could keep the euro without having to reform the country.

You can see that Adams is scared. These days, when he speaks of Greece the optimism has been replaced by occasional juvenile anti-establishment fist-waving. He knows there are no likely happy endings for Syriza, whose naivete has split the country and terrified the vulnerable.

He's rightly terrified that the unfolding disaster in Greece is bringing it home to voters that a walk on the socialist wild side is too dangerous, that ideology is no substitute for competence and that kicking explosives blows up in your face.