The left has long understood many of the many problems of outsourcing: the fact that it typically replaces at least semi-decently paid, full-time staff, with career paths and a commitment to the service ethic, with a casualised, often minimum wage, rapidly-changing group of workers who are struggling to survive – often working two or three jobs. (Even in “professional” areas such as GP surgeries and IT, relatively low pay and casualisation is the norm.) The cash not going to the work force is redirected into shareholders' pockets, all too often through off-shore, tax haven companies that fail to contribute tax to the society in which they're based, from which they’re extracting profits.

But most of all, we’ve understood that it doesn’t work. We’ve seen it fail again and again. The outsourcing of hospital cleaners contributed to a rise in hospital-acquired infections and super-bugs. Multiple government IT projects have gone seriously and expensively off the rails. Then there’s the still unfolding scandal of the ruinously expensive PFI scheme for hospitals (and other public institutions such as schools) which has just claimed its first victim, with the South London Healthcare NHS Trust going into administration. And railways and the Tube, and call centres…. the list goes on and on.

And now we’re finding, with G4S unable to guarantee that it will provide the contracted staff for the Olympics, that we’re calling on the army to help. So visitors to London will see a militarised Olympics, with expensively trained soldiers doing work that they have no training, and possibly no inclination, for. It’s difficult to know which is worse soldiers doing jobs they aren’t suited for or for that work to be done by some of the many £2.60/hour security “apprentices” that we learnt about during the Jubilee security outsourcing scandal. These arrangements for Olympics security may not be a recipe for public safety or confidence.

The writing is on the wall, but a lot more still has to be done to highlight the basic flaw of outsourcing, the reason why it does not, cannot work: the supplier of outsourced services and the purchaser have different objectives. It's as though your service is balanced on a rubber band held by two people running in different directions. Sooner or later it is going to snap, or one side be dragged back.

One small example from my working life, details anonymised for contractual reasons. At one time a widget producer had staff security people, who understood their job to be assisting in the smooth production of widgets. They knew the company, they knew the staff, they understood at least a bit about making widgets, and they used their common sense, their knowledge and some flexibility in applying the security rules to assist in the making of widgets. Then they were outsourced. New staff came in, employed by the security firm, for the purposes of security. They applied the rules as laid down by their company rigidly and inflexibly (indeed they were at risk of losing their job if they didn’t).

They didn’t know or care about the production of widgets, or that they were actively hampering their production. One told me – while I was trying to get a freelance widget worker through the system: “We’re subject to penetration tests you know.” (And no this wasn’t MI5 or Scotland Yard.) Cue rampant frustration, many wasted hours of staff time and a considerably less pleasant working environment. And fewer widgets produced.

As with so many aspects of our neo-liberal, hypercapitalist economy, outsourcing doesn’t work even in its own terms. It is a disaster, on financial, service and social grounds. We've got a government now that's ideologically wedded to it, as part of the "market knows best" religion, despite the obvious collapse of the case for that creed in the past few years, and the main opposition party that finds itself too close to its past failures to publicly recant – even if it wanted to, which given the return of Tony Blair you’d have to conclude it doesn’t. On top of that, we've got a whole generation of people in senior public service and private sector management with crisp, expensive and intellectually mediocre-to-worthless MBAs in this outsourcing "religion", who lack the knowledge of any other approach or the ability to adapt to the obvious facts under their nose.

There's a long road ahead to reverse direction from this outsourcing dead end. But we can start by saying, loudly, clearly and often, that outsourcing is a disaster. It does not, cannot, work as well as forms of organisation based on shared goals, whether they be co-operatives or public ownership at local or national level, or at least a company in which permanent, decently paid staff are working together towards the same aim.

Natalie Bennett is chair of Green Party Women and the former editor of the Guardian Weekly