Disagreements, even feuds, between prime ministers and their chancellors are nothing new. Nor are elaborately staged shows of unity and solidarity, such as the one we were treated to from the government front bench throughout yesterday's Prime Minister's Questions. Yet Alistair Darling's charge that the "forces of hell were unleashed" after he had warned in August 2008 that economic conditions were "arguably the worst they've been in 60 years" still has the capacity to wound Gordon Brown – even if Mr Darling carefully avoided naming names.

Much of the effect, of course, derives from the timing, with the general election presumed to be less than three months away. Anything that even hints at weakness in Number 10 or discord within the Cabinet is going to be seized on by the Opposition. That is just the cut-and-thrust of election politics.

But the nature of the charge is also different from the allegations about bullying which swirled around at the weekend – and so, quite probably, is the damage. Bullying has become one of those words whose meaning expands with its over-use. The voters by and large understand this, preferring a narrower understanding of the term, before it became mixed up with the modern office environment and compensation claims.

The voters also formed their impression of Gordon Brown a while ago, seeing him as serious, gruff and at times hot-tempered. People mentally substituted "bad temper" for "bullying" and saw the Prime Minister pretty much as they had done before. To be sure, a veritable army of aides rushed to Mr Brown's defence, led by Peter Mandelson, but it was the National Bullying Helpline that rapidly went into meltdown – the line is now suspended – not Number 10.

Whether or not Mr Darling had the epic battle of Gladiator in mind when he alluded to "hell being unleashed" – and it would certainly add a graphic dimension if he had – the phrase is not only memorable in itself but vividly reminds people that Number 10 during Mr Brown's tenure has had a malicious side. This includes the notorious practice of briefing against those who, for whatever reason, fall out of favour.

And Mr Darling fell out of favour in a big way. Having had the nerve to mount a successful rearguard action against moves to replace him, just as the global economic crisis threatened to engulf Britain, he then invited a journalist to visit and vouchsafed to her thoughts about the perils that lay ahead. In so doing, he called into question, even if he did not actually demolish, Mr Brown's legacy at the Treasury. Hell might indeed have had no fury like a former Chancellor scorned.

The insider view is that it was not Mr Brown, but Ed Balls – whose ambitions one day to be Chancellor have never been a secret – who was gunning for Mr Darling. If so, Mr Brown's categorical statement yesterday that he would "never instruct anybody to do anything but support my Chancellor" was entirely truthful. That he saw the need to make such a statement, however, suggests he knew the damage that could be caused by allowing it to stand.

As so often, though, there is a broader truth. Even if Mr Brown did not order negative briefings against his Chancellor, such briefings, and botched Cabinet reshuffles as well, have been a hallmark of Number 10, not just under Mr Brown, but in the dog days of Tony Blair. Voters will forgive outbursts of bad temper; managerial weakness and tolerance of malice are an altogether more serious matter.