Paul Krugman, the American economist and Nobel winner, has a favourite analogy for the politics of austerity and its supposed benefits.

He really ought to claim copyright, in English and in Greek.

"If I keep hitting myself in the head with a baseball bat," says Krugman, "and then I stop, I will start to feel better. This doesn't mean that hitting yourself in the head with a baseball bat is a good thing."

Britain's coalition government has been wielding the bat pretty freely since 2010. In Greece, an entire society has been beaten into the ground. This week, while that country's new Syriza-led government was preparing to do battle in Brussels over a "bail-out" that is sinking the ship of state, First Minister Nicola Sturgeon called the march to more austerity in the UK "deeply misguided" and immoral.

Alexis Tsipras, the Greek Prime Minister, has plenty to say on both counts. The morality of ripping an entire country apart in the name of debt recovery is one argument. Real suffering and a feeling of national subjugation are what got Syriza elected. With youth unemployment at 50.6 per cent (according to Eurostat), Greece has seen a generation destroyed. But what if Mr Tsipras and Ms Sturgeon are wrong? What if this horrible medicine is the only cure possible?

The suggestion is the real target of Professor Krugman's analogy. Expansionary austerity, so called, is one of the tenets of neoliberalism. Crudely, the claim goes that capitalism needs its slumps to produce an invigorating jolt to the system. It then requires a dose of austerity to clear out the obstacles to recovery. At their most colourful, advocates take the view that austerity is a good and necessary thing. People's lives do not often figure in their calculations.

So has Greece started to feel better by the Krugman analogy? Hardly: unless Syriza makes progress in Brussels this weekend, the baseball bat will go on being applied. But are there signs of improvement that might one day justify all the country has endured? You could put it another way: when does neoliberalism begin to deliver?

The Greek debt crisis was inaugurated in October 2009 when Pasok won legislative elections and revealed a budget deficit - concealed hitherto - standing at 12.5 per cent of GDP. As the agencies took cleavers to Greece's credit rating, the country owed 301 billion euros, mostly to private lenders. This was 127 per cent of GDP. The first of many "austerity packages" was launched within weeks.

As even economists admit, there is a problem with those, human misery aside. If a government cuts spending, GDP, predictably, is affected. In fact, the debt-to-GDP ratio increases. So it is that in 2015 the Greek debts that once stood at 127 per cent of GDP have touched 175 per cent. The country that owed 301 billion euros now owes 315 billion. The sole difference is that the bulk of the debt is these days due to the IMF, the European Central Bank, and European governments.

The UK's condition is nothing like as grim, even if a brush with deflation lies ahead. If you believe coalition ministers, indeed, their "long-term economic plan" is paying off nicely in terms of jobs and growth. But Ms Sturgeon was only stating facts when she told her audience at University College London that George Osborne, the Chancellor, has missed his debt and deficit reduction targets time and again.

The past five years have been hellish for Greece, but no picnic for Britain. In his "emergency budget" of June 2010, Mr Osborne promised it would all be over by now: a £149 billion budget deficit would be gone by the end of the parliament. Yet in January it was announced that public sector borrowing for the first eight months of the financial year was £86.3bn. The national debt, as a consequence, was up by another 6.8 per cent. Collectively, we now owe £1,483.3bn, or 80.9 of GDP.

Revenues have not been coming in as Mr Osborne anticipated: austerity is like that. So in what sense can it be said to have worked? What have the last five years been for? What is therefore so unthinkable about Ms Sturgeon's confessedly modest proposal for 0.5 per cent increase in public spending to allow the economy to grow and - not the least of her priorities - give people a break? By her own account, economics without a human dimension is of no interest to the First Minister.

Her policy is hardly the full-blooded defiance of Syriza. It leaves questions of taxation more or less unanswered. Politically, it counts as a statement of intent in possible negotiations for a confidence-and-supply deal with Labour. But even as a mild rejection of austerity it will resonate. After all, and despite his record of failure, Mr Osborne is planning another £21bn of cuts to achieve a budget surplus - still another solemn ambition - by 2020.

Greece is the object lesson, indeed the moral lesson. None of its partners would want to see it forced out of the eurozone, but most are determined to make it abide by what Germany's Angela Merkel calls "the rules". They could easily be mistaken for her rules. If Greeks want to keep the euro - and they do - they cannot purge debt through devaluation. But the rules say, supposedly, that they cannot restructure their debts in any manner they please.

The existing Greek bailout will have expired within a fortnight. At that moment the country will require another 7 billion euro loan. If no agreement is forthcoming, no money will be advanced and the government of Greece will run out of cash. But Mr Tsipras cannot return to Athens with just an extension to an austerity programme that has thrown 2.5 million people into poverty, even if he was so inclined. Syriza was elected to end this nightmare.

The "far-left" Greeks of caricature have already compromised. Rather than reject the entire bail-out deal, they have concentrated on the 30 per cent (they say) that is "toxic". Eurozone ministers, fretting over attitudes among their own electorates, have managed only the crudest response: stick with the programme and we might be able to negotiate over the details.

Two worlds are in collision. The bailout deal agreed by previous Greek governments calls for still more cuts to the public sector and pension "reforms" liable to impoverish pensioners further. Syriza wants to raise the minimum wage, help people to pay electricity bills, and hire a few civil servants to keep the country running.

The attitudes involved are diametrically opposed. One subordinates society to what is recognised as economic reality; the other says economics has parted company from human reality. You could say, for contrast, that Ms Sturgeon proposes a middle way while the main Westminster parties remain wedded, with no appearance of doubt, to austerity.

The real fear among Europe's politicians and financiers is that even the appearance of a victory for Syriza will set off a contagion across the continent, in Spain not least, that sees other countries rebel. It wouldn't do for word to get out that the elites were utterly wrong about the baseball bat cure.