Suddenly Gordon Brown deploys wit against David Cameron, a stylistic U-turn as momentous as some of the policy reversals that have marked his leadership. Until recently Brown avoided overt attacks of any kind, preferring stealthy onslaughts in the form of policies aimed at leading the Conservatives into various traps. This week at Prime Minister's Question Time, the most significant exchange for more than two years, Brown put stealth to one side and opted for mockery as part of his pre-election repertoire.
There is a minor mystery as to why he has waited for so long. Brown was once an effective parliamentary performer and a witty one too. He was never as nimble-footed as Tony Blair and always prepared too diligently, but in the late 1980s when he stood in as shadow chancellor for John Smith, his performances against the formidably self-confident Nigel Lawson won him accolades across the political spectrum. Even as Chancellor, though far more buttoned-up, he saw off a succession of bright Tory politicians with ease, from Michael Portillo to Oliver Letwin. Yet Cameron has made Brown seem hopelessly leaden-footed.
These exchanges matter. One way or another they seep through to the wider electorate. Cameron shaped the dynamics of the last two years with his brilliant soundbite during the first PMQs after the early election was cancelled in 2007. He declared to a ghostly Brown sitting opposite that he was "the first Prime Minister to call off an election because he was afraid he was going to win". The words ushered in two years of prime ministerial hell.
I describe Brown's wooden performances as a minor mystery because it is easily solved. His early strategy, one that has not been entirely junked, was to present himself as an almost apolitical father of the nation. "I am looking for a consensus on this issue," was one of his favourite phrases. As he saw it, an apparent consensus-seeker could not spend half the time attacking his main opponent. The perverse and predictable outcome was to concede huge amounts of space as he struggled to find an authentic prime ministerial voice.
On Wednesday he found it. He is most at ease in the Commons tormenting opponents, so he might as well show it. Privately Brown has been livid for years at the way he is portrayed as out of touch when he comes from a modest background and loves sport with a passion shared by many voters while the wealthy Cameron is seen as a regular guy. For the first time he linked the "playing fields of Eton" with Cameron, Zac Goldsmith, non-domiciles avoiding tax and of course the Conservatives' policy to scrap inheritance tax, a proposal that has produced his first good jokes since becoming Prime Minister.
Gerald Kaufman once told me that Harold Wilson learnt to have a sense of humour. If this was the case Wilson was a stunning pupil, wit being his most powerful weapon to the very end of his career. Until now Brown has done the opposite. He has learnt not to have a sense of humour when he had one.
The reference to Eton has provoked some headlines about a return to "class warfare", implying that a leader's background is off limits or counter-productive. This is odd because leaders often refer to their backgrounds themselves if they consider them to be useful. Margaret Thatcher spoke often in the early years of her leadership about her father's shop in Grantham. Indeed she based an entire economic policy on it, pointing out that her father did not spend more than he earned, an insight that led to a deep recession in the 1980s and one that seems to be guiding the Conservatives' economic policy now. Sadly Thatcher's father has had more influence on Britain's economic direction than Keynes.
John Major too made much of his modest background, especially during the 1992 election, where during one party political broadcast he pretended to be excited at seeing the location of his childhood home in Brixton. Cameron will not be taking part in an equivalent broadcast next year, but that does not mean his opponents should be quite as reticent. When a tired government seeking a fourth term is accused of being out of touch it has a rejoinder of sorts. In terms of social background its members are more connected to most voters than those fresh-faced figures who seek a first term.
The evidence usually cited for the dangers of "class" politics is the Crewe and Nantwich by-election, a campaign in which some Labour activists dressed up in toffs' uniforms. Labour was slaughtered and the Conservatives gained the seat with a swing of such magnitude that no senior Labour figure dared utter the word "Eton" or "Bullingdon Club" for a long time. But the by-election, like so much else in politics, has acquired a mythology that bears little relation to reality. Labour lost because the contest took place in the middle of one of the most disastrously chaotic sequences for a government in recent times.
Brown had refused to pay compensation for low earners who had lost out from the abolition of the 10p rate and had then given in to an army of rebels. Petrol was soaring in price. No 10 was at its most dysfunctional. I could go on. The silly toffs' stunt was peripheral and, as far as it had any impact, probably reinforced the sense of a Labour party becoming increasingly desperate.
That is obviously the danger for Brown now in playing this particular card, that it is perceived as part of a core vote strategy in which Labour looks inward in a pathetic attempt to avoid a near wipe out. But that is not the actual strategy, whatever the perceptions. On the contrary Brown seeks to flesh out New Labour's most famous soundbite, the one in which he claims to act for the many and not the few. It is the opposite of a core vote strategy.
Whether it will work in changed circumstances is another matter. What is more significant than the precise strategic calculations is that Brown has decided to attack his main opponent overtly and to deploy humour in doing so. At the very least it will do him no harm. My guess is that it will do him quite a lot of good.