The great mercantilist Cameron, recently returned from the Orient, came to the Commons today to answer prime minister’s questions. Unfortunately, all he ended up trading was quotations. Insults would have been too spiced for this semolina fare.

Harriet Harman, still covering for junior Miliband while he finishes off the nappy shift, and wearing her outfit that suggests the recent massacre of several giraffes, wanted to know about how many fewer police officers there would be as a result of the Government’s cuts. Ms Harman came armed with a quote from the GM himself – uttered during his pre Marco Polo period – to the effect that he would send back any Cabinet minister who came to him with a plan for reducing “front-line” staff.

As an exercise in exposing Mr Cameron’s wanton (or should that be wantong) hypocrisy, this would have been more effective if the prime minister were actually owning up to hacking away the thin blue line.  Mr Cameron, however, was doing no such thing.  It was, as ever, the poor schmucks in HR, IT and, on this occasion, vehicle maintenance, who were going to get it in the P45.

Safe in the knowledge that – despite presumably their capacity for throwing a spanner in the works – car mechanics command but a nugatory slice of the nation’s affection, Mr Cameron had his own quotation to fling back across the despatch box at giraffe-woman.  This was from Alan Johnson, who at the time was the shadow home secretary. Or rather the quote was from Andrew Neil, who has never been the shadow home secretary as far as any of us can recall, and it took the form of a very long question at the end of which Mr Johnson had conveniently said “no”.  At least that was convenient for Mr Cameron since it was just the answer he had needed to make his point. The fact that, by this juncture, we had started to lose all interest in what the point was, need not detain us.

It seemed to detain Ms Harman, however, because instead of, as is her right, smartly changing the subject to something fruitier like the Irish financial crisis, she ploughed on with police numbers, bringing the focus onto Greater Manchester and dragging the chief constable of that fine city into her argument. Inevitably, Mr Cameron had his own quote from the chief constable to throw back at Labour’s deputy leader, and so the trading went on.

What does he say, said Ms Harman finally, to the people of Manchester who will be deeply worried about the cut in police numbers? To which the aposite reply might well be “just thank your lucky stars you don’t live in Liverpool”. But Mr Cameron declined to say it and so Ms Harman’s little notebook of quotable quotes must remain padlocked for another day .

Later on, in response to a question from the Labour backbencher Bill Esterson, the prime minister found it in himself to put in a plea for faster wheelchairs, briefly conjuring up the fascinating image of Britain’s paraplegics breaking the land-speed record, before correcting himself to mean something much more insipid.  Then the next question was about Short Money which, in the spirit of the prime minister’s clipped style, might have been prelude to a rant about Government cuts in the funding for dwarves. Short Money is in fact the cash handed over to the opposition to research and write down the prime minister’s uncircumspect quotations.  It is, it turns out going up by a million or so, presumably on the condition that it goes to the front-line.

Mr Andrew Griffiths, the Conservative asking the question, thought that, in keeping with the age of austerity, the Labour Party ought to pay some of this largesse back. Labour should be kept short as unfortunately – or perhaps fortunately – Mr Griffiths did not think to say.