David Prosser: Mervyn's message to the politicians: this is an election to lose

Outlook: So it is not just the Prime Minister who makes the occasional unguarded remark. Still, while the story of Mervyn King's comments to the economist David Hale – brought to light by the indiscretion of Mr Hale rather than a rogue microphone – will no doubt cause some embarrassment to the Governor of the Bank of England, Mr King has only said what many other people are thinking.

All three political parties are continuing to cop serious flak for their failure to spell out the detail of how they would get the public finances back on track – not least from the coruscating report published by the Institute for Fiscal Studies earlier this week. But cut them just a little slack: all of them are scared this detail is so unpalatable that offering too much of it would be an invitation to severe punishment at the ballot box on Thursday.

Mr King's analysis goes a little further. He thinks the coming age of austerity will be so difficult that even with a five-year term of office, no government is going to be able to succeed in slashing the deficit without kissing goodbye to their chances at the ballot box next time around and possibly at several subsequent polls.

In other words, Mr King shares the politicians' suspicions about the way in which people vote: that while we all know some rough medicine is needed and usually say publicly that we want to know just how bad it will taste, once we're cloistered in the privacy of the polling booth we punish those who have the gumption to force the stuff down our throats.

There is some basis for these suspicions. The Labour Party is, for example, still haunted by its experience at the 1992 general election, when party strategists blamed defeat on a manifesto that was overly frank about tax rises.

But politicians who tackle fiscal crisis are not always thrown out of office. The think tank Policy Exchange has published a detailed analysis of fiscal crises from the past 100 years in both this country and elsewhere. Concentrating on the UK, it identified six occasions on which British governments were forced to slash spending or raise taxes (or both); four of these administrations suffered electoral retribution, but two did not.

Of the exceptions, the most obvious example is the Conservative government of the early eighties, which won three further elections despite the extremely challenging consequences of its economic programme during its first term of office.

You might argue, however, that Mrs Thatcher's first government would have been punished too in 1983, had it not been for the Falklands War and the split of the SDP from Labour. For that reason, and in the current political context, the first exception is much more interesting.

Policy Exchange highlights the experience of the 1930s, when the Labour government collapsed while trying to agree post-Great Depression cuts, to be replaced by the coalition National Government. Four years after forcing through a painful emergency budget in 1931, this coalition clung on to power at the 1935 election.

Is there a lesson for our time? If so, it may just be that at times of economic crisis, political consensus is needed if the electorate is to be convinced to take its medicine without revolting. Coalition government could be just the thing.