£25bn here and £25bn there, and pretty soon you’re talking real money. It has been absolutely apparent for at least five months that nationalisation represents the only realistic means of safeguarding the astonishing sums of taxpayer cash shovelled into Northern Rock to rescue the bank from the consequences of managerial incompetence.

Finally Alistair Darling has gotten the message. The erstwhile bearded Trot himself has brought the UK’s number five mortgage lender within the ambit of proletarian property relations. Only another 199 of the top 200 monopolies to go and Britain becomes a workers’ state, comrade. Shame the government didn’t see things the same way when Rover was going tits up. But in the financial services-driven British economy of today, grubby little manufacturing concerns seem somehow not to count.

What this episode proves is that nationalisation really is no worse than, say, bestiality, ebola, paedophilia, diabolism or any given combination thereof, and could at least be seriously discussed in other contexts.

Yet even as an advocate of various forms of common ownership – varying from nationalisation to municipalisation and workers’ co-operatives, depending on circumstances - I don’t see any special merit in bringing a one-time building society that got too big for its boots into the public sector.

It was surely right to try to protect depositors; the greedy shareholders can frankly swivel. As economics textbooks make clear, the dividends they have been pocketing all these years are their reward for putting their capital at risk.

The principle is the same as having a tenner on a gee gees; if you lose the bet, you don’t get your money back. Without state intervention, Northern Rock would be worthless. The whinging from the likes of RAB Capital is nauseating.

The danger with today’s development is that public ownership will be regarded simply as a means of bailing out companies up a well-known creek, while the positive case for such measures will be disregarded entirely.

Let’s get away from the lie that the unfettered market economy the Tories and New Labour alike have nurtured has been a runaway success. It has wrecked manufacturing industry, and reduced British workers to the lowest level of employment rights in the industrialised world.

Privatisation has, of course, freed taxpayers of the need to pump hundreds of millions of pounds a year into inefficient nationalised industries. Now we just pump billions of pounds a year into inefficient privatised businesses instead.

Selling off such natural monopolies as the railway system and basic utilities simply licences the fleecing of the customer for the sake of private profit.

Legally speaking, the first duty of a private company is act in the best interests of shareholders. But anyone with any sense wants hospitals to act in the best interests of patients, schools to act in the best interests of pupils, and water and electricity companies to act in the best interests of consumers.

The notion that private sector management is inherently superior to, or necessarily ‘more dynamic’ than, public sector management surely stands as comprehensively shredded as the last set of Enron accounts. Consider such triumphs as Railtrack, Equitable Life and Marconi.

That’s why the railway system is subsidised by the taxpayer to the tune of £5bn a year, three times what was paid out to BR. According to the House of Commons transport committee, the tube now costs the taxpayer a staggering twenty times as much as it did when it was in the public sector.

Some industries are – as economic theory used to recognise - natural monopolies. There is no point building a second set of water pipelines and installing a second set of taps in every household.

But in order to control or influence a major company, the choice is basically between regulation, financial incentives and public ownership. Given that private firms exist to maximise profits, it is perfectly reasonable to legislate that they do not do so by cutting down rain forests or using toxic chemicals.

It is unrealistic and unreasonable to try to use regulation to ensure that it pursues a goal entirely different from maximising profits, such as satisfying social needs within a framework of sustainable growth. After all, the company can be taken over and the management sacked if it strays from the profit maximisation path.

That’s were democratic social ownership comes in. The right have won the propaganda war on this one for more than two decades. But if the left cannot put the idea back in circulation, nobody else will.

* Cross-posted from Dave’s Part