Matthew Norman: It would be a duller country without Cherie

She's the sort of pushy, very bright girlfriend the young Ken Barlow would have brought home

Should any budding Jane Austen be planning a roman-à-clef about our self-styled "Trailblazing First Lady of Downing Street", I am pleased to offer both a title and a micro-précis of the plot for any passing publisher. Cents And Insensitivity, a comedy of bad manners, will tell the tale of the driven girl from a Merseyside council estate who, for all her undoubted intellect, had the most colossal blind spot to the perception of her quest for dollars.

Sometimes, those bucks were Australian, as in the £100,000-worth Cherie Blair trousered for speaking on behalf of an Aussie children's cancer charity. Sometimes, they were American, as with the £30,000 earned this week for that brief, but contentious, address in Washington. But always, whether US$ or A$, her passion for the currency, and her bemused sorrow at the resulting public disapproval, suggests Dollars And Dolours as an alternative working title. Cherie is deeply saddened once again, we are told, to find her commercial ambitions derided and disdained back in Tall Poppy Syndrome Blighty.

In mounting a defence, or rather a plea in mitigation, there seems no point in disputing the charge of hypocrisy. No amount of legal sophistry could do that. The facts are too plain and beyond dispute.

Here we have a defendant who stood for parliament citing two TBs, neither of them her husband, as her great political influences. One was her father, that booziest and most fecund of actors Tony Booth, an old-fashioned, simplistic leftie. The other was Tony Benn, an enchanting puritan whose version of hedonism is a pot of PG Tips and a briar full of rough-cut shag. Neither, we may presume, would wildly approve of Cherie's nice little earner, nor of her reported outrage at the notion that any money trousered because of her role as PM's soul-mate should go to the deserving poor.

The high-profile human rights lawyer who accepts the hospitality of the brutally repressive Egyptian government; the self-proclaimed socialist who holidays with that borderline neo-fascist Silvio Berlusconi; the woman who constantly complains of media sexism, yet bitches to Piers Morgan about the poor quality of Victoria Beckham's skin ... No, not even the most gifted advocate on Michael Jackson's team would bother to deny that Cherie is a hypocrite.

Yet I don't believe it's the hypocrisy that so offends. Cherie's husband leads a government stuffed with characters who have abandoned every belief that defined them 20 years ago, and we blithely accept this as the way of the world. Alan Milburn, an ex-Trot, picks up a small fortune for advising a private health firm, and no one gets too aerated. The former communist John Reid owns a Westminster house worth £4m, and no livid articles are written.

No one is ashamed any more about the naked desire for, and enjoyment of, money, and to one half of a couple bringing in the best part of £500,000 per annum, £30,000 (£18,000 after tax) is chicken feed - not a 10th of the compensation needed for the appalling personal publicity it generated. As for the timing of this Washington gig, this is so dementedly foolish as to be positively endearing. How can you not warm to someone so ostentatiously brainy who cannot comprehend the umbrage at her earning one and a half times the average British wage for a brief appearance on the very eve of her husband's attempt to persuade the leader of the free world to eradicate global poverty? What is it that makes human beings intriguing, after all, if not flaws and paradox?

No, what we British really dislike about Cherie is the perceived mixture of vicarious ambition and brazen vulgarity. She is seen as half Lady Macbeth, presiding Hillary-style over Downing St seminars and fuelling her old man's feud with the chap next door (Peter Mandelson has a letter from Cherie, upon his first "resignation", speaking of Gordon in fantastically vicious terms), and half Lady Muck, the working-class girl with ideas of grandeur far beyond her station.

She's exactly the sort of strong, pushy, bright girlfriend the young Ken Barlow would have brought home in a university vacation, whose refusal to settle for what the accident of her birth had given her would have aroused the contempt of Uncle Albert Tatlock and the gang. If Elsie Tanner (played by her one-time common law stepmother Pat Phoenix) had mentioned Cherie in the snug of the Rovers Return, Ena Sharples would have sucked a mouthful of milk stout through visibly thinning lips, turned to Minnie Caldwell, and declared her "no better than she should be".

And yet in important ways, this hybrid Lady Muckbeth is far better than she might be. Her work for charity is sincere, and carried out quietly with no apparent desire for positive headlines. At Chicken Shed, the magnificent youth theatre company which integrates able-bodied actors with those with special needs, they speak rapturously of her generosity with both time and support. Others involved with charities (here, if not Down Under) tell a similar story.

So if some of her life is lived out like a contestant on Supermarket Sweep, charging the trolley around the designer stores and stripping the racks like a one-woman plague of locusts, an equal part is devoted to the unostentatious doing of good. If she comes out level on the self-indulgence/charity balance sheet, this probably gives her an edge over most of us who have spent such happy years teasing her for the avarice.

Meanwhile, to regret that Cherie isn't more like her predecessors is to ignore the spirit of the age. Mary Wilson had her mawkish poetry, Audrey Callaghan was as little seen and heard as Mrs Krushchev, Denis Thatcher (with whom Cherie idiotically compares herself) was wealthy and uninterested, and Norma Major's heraldic motto would be: "She boiled the peas, and kept herself to herself". Any embarrassing relatives were brothers (Terry Major-Ball) or sons (Mark Thatcher), never spouses. But that was then. Now, it is the ultimate fantasy of every thrusting council estate girl and boy to find fame and wealth, to go on glamorous holidays, to be treated to designer gear, and to brag in The Sun about their rampant sex lives. Who is Cherie if not their patron saint?

In a couple of years, Sarah Brown will be in No 10, and a couple after that it may well be the equally retiring Gillian Clarke or Doreen Davis. They will never style themselves "trailblazing First Lady of Downing Street", and the greed and the grandeur will evaporate. And then, when she and Tony have taken the trolley dash to the US, where they so obviously belong, I suspect that Cherie will be strangely missed. If nothing else, this will be a duller country without our very own Lady Muckbeth.