One trouble with CTCs, said Labour's Education Spokesman Jack Straw in 1990, was that sponsors were "second-order companies whose directors were interested in political leverage or honours".

Their interests are reflected in the very large proportion of academies that have Business and Enterprise as their specialism. Seven of the first forty six have it as the sole specialism, and another nineteen have it as one of two or three specialisms, making twenty six in all with a Business and Enterprise specialism - well over half.

Two million pounds, a fraction of the likely capital cost of an academy, turned out to be far too much, even though the state was going to pick up the tab for the running costs in perpetuity. Quite soon, the money expected from sponsors had quietly become "up to £2m".

And then, ever so quietly, three dread words were added: "in cash or in kind". Help "in kind" means almost anything - say the services of an elderly executive, too senior to fire and too tired to be any use, the value of whose time, generously estimated, can be marked down as a generous contribution to our beleaguered education system.

There are sponsors who do put in the full amount. But £2m is still a drop in the ocean - especially when you remember that a corporation can claim tax relief for the money, reducing its real contribution to an estimated £1.2m.

By April 2005, desperation to find private sponsors reached fever pitch, so much so that the government adopted the cheap trick of a cut-rate offer if you buy more than three. Sponsors have been told that if they fund three academies, the "price" for each one thereafter will be only £1.5m rather than the standard £2m.

In return for that upfront cash towards the capital costs of the new school, sponsors are given more or less absolute control of the curriculum, ethos and staffing. The government will provide the remainder of the money, typically about £23m.

Even with this sort of inducement, sponsors proved very hard to find. A few expressed an interest, only to withdraw as they saw the depth of local hostility. Those who stayed were remarkably reluctant actually to part with cash. In May 2006, the Guardian reported that most of them had not paid the £2m. Four academies that had been open for nearly a year had not received a penny from their sponsor. With 27 academies up and running, sponsors had paid up only £26m.

It's partly for this reason that the government suddenly announced a revolution in the way the academy programme was to be run. Sponsors would no longer have to put any money at all upfront. Instead they are invited to make "endowments" over the years.

"Also announced today is a new sponsorship model for Academies which will help strengthen the long-term investment of sponsors in Academies through new charitable endowment funds. The change will mean sponsor contributions - which remain the same - will in future go into long term endowments to be spent on the school's educational needs and to counter the impact of disadvantage. Thanks to savings made by a more cost-effective building and procurement process through Building Schools for the Future, the sponsorship contribution is no longer required for building costs". (Parent power and new independent report give fresh backing to Academies, DCSF 27 July 2006)

Education Secretary Ruth Kelly once made a totally fatuous remark that we need business sponsors because "business doesn't tolerate failure". By then the search for business sponsors was self-evidently failing, and other sponsors - churches, charities, even the much-despised local authorities - were being dragged in to take their place.

There is a strong relationship between sponsors and the companies that make their profits out of privatising services like schools and hospitals. Sponsors often hire these companies to run academies, as 3Es was appointed to run Bexley Business Academy. And it is these companies, as the register of interests of MPs and Lords shows, which tend to complete the slightly grubby circle by employing former ministers and officials as parliamentary advisers. There is nothing to stop former education minister Lord Filkin being a director of Serco, which manages schools, or Charles Clarke, former education secretary, being a non-executive director of LJ Group, which is seeking work under the government's Building Schools for the Future programme, the main driver of the city academy programme. But it adds to the atmosphere in which some sponsors pulled out when they saw the strength of local and national opposition. Those who stay the course often feel victimised and misunderstood by the media. "It's a lot of hard work and you have the press continually doubting your motives," says Steve Chalke, founder and boss of Christian charity the Oasis Trust. And that, no doubt, is true, but is it surprising?