Controversy follows the private finance initiative (PFI) and its near cousin the public private partnership (PPP) as surely as night follows day. The newspapers, especially those with a political axe to grind, are full of stories of shoddy buildings, escaped prisoners and corporate greed, while the Government’s political opponents are never slow to make the accusation that PFI is no more than an accounting trick to disguise the true level of public spending.

The clamour reached a crescendo over by far the biggest PPP established to date, the one to upgrade the infrastructure of the London Underground, which was finally completed last year after some years of hard negotiations – and at a price far in excess of the original estimates.