There was trouble with the priest because Gale Howard and Tony Booth had picked the godless name Cherie to register the birth of their newborn. Vera Booth, formidable grandma, had charge of the baby and knew that a Roman Catholic child could be baptised only with the name of a saint. So an un-Booth like compromise had to be reached - and the future prime minister's wife was christened Theresa, after the 16th-century Spanish abbess.

It was an unconsciously prophetic choice. For the energetic, ambitious nun met much trouble and opposition from authority. One papal nuncio described her as “a restless woman rambling about the country, indocile and contumacious, the inventor of false doctrines with the appearance of piety...and a despiser of the apostolic precept that forbids a woman to teach.” I wonder if his surname was Campbell.

It has always puzzled me why Cherie Blair has attracted such levels of dislike, to a level of vitriol scarcely believable. Never having met her, I remained neutral, occasionally dropping head in hands at some reported gaffe or colossal error of judgment (such as allowing herself to have any involvement with the con man Peter Foster) and wondering how she could so let the side down.

I should explain that “side”. I am eight years older but we have much in common: both born into the aspirational Liverpool working class, both clever, rebellious grammar school girls, both with grandmothers who cleaned, both anxious about being “good enough” in class terms, both the first in the family to go away to university, both made to feel “wrong side of the tracks” by a middle class boyfriend's family, both marrying someone next rung up on the class ladder (whom she beats in the academic stakes), both bemused by the arcane customs of Balmoral - and both driven by this everlasting nervy compulsion to prove.

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Cherie Blair reveals her husband is advising Gordon Brown but says he did not trust him enough to stand down early

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• Cherie Blair: motherhood, makeovers and making ends meet – my life in Downing Street

• Cherie Blair: the secrecy and sadness behind a remarkable memoir

Multimedia

• Full coverage: Cherie Blair autobiography

Background

• My complex life in Downing Street

• Secrecy and sadness behind memoir

• Leo: my miracle baby at 45 (and yes, he did have the MMR jab)

• The night I hated Tony

Background

• Miscarriage: ‘I'm afraid the baby's dead, Mrs Blair'

• The Queen and I: relations with the royals

• Cherie Blair's face-off with Campbell over Caplin

• Peter Foster and the ‘scandal' that never was

Prove what? There's the rub. Determined to read the autobiography at one sitting to be scrupulously fair and with a predisposition in Cherie's favour because of all the above, I am as puzzled as ever by my Scouse sister. Wanting her to prove she could write a good book reflecting on an admirable and fascinating life, it's hard not to be disappointed by her sloppily written “blurt”. For example, if the lawyer is not bothered to check that the Editor of The Times in 1986 (the time of “Fortress Wapping”) was Charlie Wilson, not (as she states) Peter Stothard - when “as loyal Party members on the side of the unions”, the Blairs felt involved with the dispute and had moved into a house previously owned by Stothard - how many other careless slips are there?

Yet Speaking For Myself is a riveting read, the total lack of literary style and thoughtfulness not quite compensated for by its energy. Did she have to write exactly as she speaks: “ruddy” this and that? The most interesting aspects of her narrative lie in the story of her “disjointed” early life - and not with the now familiar political gossip. Did she or did she not mouth “That's a lie” when Gordon praised Tony at conference?

By the time you reach this point, you decide that she probably did. I wonder at the 30-odd references to class in this cheerily painful book. With all your brains and talent and your good heart, Cherie, could you not deal with this?

Not with such terrible fear stalking every step. The little girl was left with her grandparents until she was 2, her actor parents conspicuous by absence; she didn't see her new sister until the baby was 3 months old and was then shocked to be left again, this time with her mother, when to her, grandmother was “Mama”. A “sense of abandonment” and perennial “twinges of anxiety” would remain with her always - with the feeling that she was “non-existent” to her father.

Is it any wonder that Cherie's life was to be marked by her desperate - and lonely - compulsion to wave a hand in the air and cry out: “Please, look at me!”? No level of achievement is ever quite enough, especially when you must play second fiddle to the husband whom you love, but also resent.

So at the very end, Cherie cannot resist tossing her notorious jibe to the waiting press and Tony is furious. Like much of this book, her account of her own failing is quite touching. “We had discussed it so often; leaving was ...to be done with dignity and grace, and what I had just done was neither gracious nor dignified”.

Still you ask - why? Here is a woman with an excellent brain who has still not mastered simple speech. But, like her delight in free holidays and her needy clinging to Carole Caplin, I do not find this “wicked”, as some might - just painfully fallible and human. Our Cherie's done well for herself. She's now free to use her energy for the good that she believes in. But let her do it quietly, with some Carmelite contemplation.

Speaking for Myself: The Autobiography by Cherie Blair
Little, Brown, £18.99; 432pp Buy the book here

First Lady Writers:

Hillary Clinton
Living History (2003)
Hurt her wrist signing 20,000 copies but upped her advance by tackling the Lewinsky affair.

Barbara Bush
A Memoir (1994)
30 years of diary entries inspired a 532-page tome.

Eleanor Roosevelt
The Autobiography (1961)
The grandmother of First Ladies presented a multi-volume magnum opus.

Nancy Reagan
The Unauthorised Biography by Kitty Kelley (1991)
Repeated rumours of an affair with Frank Sinatra.

Marcia Falkender
Downing Street in Perspective (1983)
Did Harold Wilson's secretary really run the country?

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