If the coalition is indeed going to deliberately inflate the public sector deficit as an all-purpose justifier - the Gideon/Fraser Nelson strategy - a key element in what they will have to get the OBR to accept will be the treatment of Private Finance Initiative/Public-Private Partnership projects. Certainly, complaining about AirTanker would give that impression.

Everyone knows about PFI - at least on the left, it’s one of those things that everyone has a conditioned reflex response for. You just need to say the acronym and people start salivating with rage. The idea was that rather than borrowing money itself to build things, the government would have the contractors building the things borrow the money, and then essentially sell them to the government on a hire-purchase model.

This was introduced by the last Tory government just after the masters of fiscal rectitude had set what was then an all-time record for an annual budget deficit as a percentage of GDP; the point was fairly explicitly to keep capital investment projects off the public sector’s books. A variety of increasingly specious arguments were invented to justify the whole project - private management was inherently more efficient, although the “public sector comparator” used to assess PFI contracts was usually set at worse levels of efficiency than the public sector managers were actually achieving.

“Reputational risk” to the government if it was seen to be spending money was assumed, quantified, and chucked in the mix - a procedure that was never more than a fudge factor dependent on a range of imponderable variables, and which turned out with wearisome inevitability to always produce the right number to justify the PFI. The peak of this lame fuckaround was achieved with the privatisation of London Underground maintenance, which has in the meantime needed renationalising, with the last remaining PFI contractor being bought out in election week.

None of this was particularly principled, or for that matter stable; perhaps the summit of ridiculousness was achieved after the great financial crisis, when certain PFIs which could no longer be financed privately were refinanced by the government. Clearly, the PFI religion was so important to some people at the Treasury that they couldn’t bring themselves to go ahead on a “traditional”, “conventional”, or perhaps just normal basis.

But the especially interesting and unprincipled bit is the role of various Tory politicians. Specifically, William Hague and Kenneth Clarke, the survivors from the Major government. For these two, PFI contracts weren’t debt in 1996 - but somehow they are now. PFI was responsible, daddy-party, serious, etc in ‘96; it is profligate, socialist, unserious, etc in 2010.

Both would be well advised to shut up in the House on the topic.