THE DIARY OF BRIDGET JONES

Saturday 14 May

9st 1, alcohol units 5, cigarettes 15, Instants 1, Lottery £2

My mum rang and I decided to confront her about the late-in-life smoothie I saw waiting for her outside the Dickens & Jones coffee shop.

"Oh, you must mean Julian," she trilled. This immediately was a giveaway. My parents do not describe their friends to me by their Christian names. It is always Una Alconbury, Geoffrey Coles, Brian Enderby: "You know Brian, darling - married to Monica Enderby who's in the Lifeboat." It's a sort of gesture to the fact that they know in their hearts I have no idea who Monica Enderby is, even though they're going to talk about Brian and Monica Enderby for the next 40 minutes as if I've known Brian intimately since I was four.

I knew straight away that Julian would not turn out to be involved in lifeboat luncheons, nor would he have a wife who was in any Lifeboats, Rotaries, or Friends of St George's. I sensed also that he was not Julian but Julio, and that she met him in Portugal, before the trouble with Dad. I sensed that, let's face it, Julian was the trouble with Dad.

She denied it. She even came out with some elaborately concocted tale about him bumping into her in the Marble Arch Marks & Spencer, making her drop a new Le Creuset terrine dish on her foot and taking her for a coffee in Selfridges, from which sprang forth as if by magic a firm platonic friendship based entirely on department store coffee shops.

Why? Why, when people leave their partners because they're having an affair with someone else, do they think it will seem better to pretend there was no one else involved before they left? Do they think it will be less hurtful for their partners to think they just left because they couldn't stand them any more, and then had the good fortune to meet some tall Omar Sharif figure with a gentleman's handbag two weeks afterwards while the ex-partner is spending his evenings bursting into tears at the sight of the toothbrush mug? It's like those people who instinctively invent a lie as an excuse rather than the truth, even when the truth is actually better than the lie.

I once heard my friend Simon blowing out a girl - on whom he was really keen - because he had a spot with a yellow head just to the right of his nose, and because he had gone to work, owing to severe laundry crisis, in a ludicrous late Seventies jacket, assuming he could pick his normal jacket up from the cleaners at lunchtime, but the cleaners hadn't done it.

He told her he couldn't come because his sister had turned up unexpectedly for the evening and he had to entertain her, adding wildly that he also had to watch some videos for work before the morning. At which point, the girl reminded him that he'd told her on the previous date that he hadn't got any brothers or sister - which he hadn't - and why didn't he come round and watch the videos at her place while she cooked him supper? But he didn't have any videos to bring round and watch - and a quagmire of lies ensued that ended with the girl convinced he was trying to chuck her on the second date and go out with someone else and Simon spending the evening drinking alone in his Seventies jacket.

I tried to explain to mum that she wasn't telling the truth, but she is so suffused with lust that she has lost sight of, well, everything.

"You're really becoming very cynical and suspicious, darling," she said. "Julio's just a friend. I just need some space."

So why, when I saw her in the Dickens & Jones coffee bar, did she have a carrier bag full of Charnos bra-slips?

Sunday 15 May

Awake, alone, to find myself imagining my mother in bed with Julio, which raises a complicated quagmire of feelings: repulsion at vision of parental, or rather demi-parental, sex; outrage on behalf of father; heady selfish optimism at having another 30 years of unbridled passion ahead of me (not unrelated to frequent thoughts of Joanna Lumley); jealousy; extreme sense of failure and foolishness at being in bed alone while my mother, aged 60, is probably just about to do it for the second ... oh my God. No. I can't bear it. Must get coffee.

Maybe their generation are just better at getting on with relationships. Maybe they don't muck about being all paranoid and diffident. Maybe it helps if you've never read a self-help book in your life.

Open paper to discover that the Henley Centre says that people have taken to ignoring the broader picture and giving themselves little "boomlets" - shopping sprees that they cannot afford and so on - to cheer themselves up, which rapidly peter out. I sympathise with this entirely.

I realise that my entire life has become a series of boomlets: cigarettes, drinks, instant lottery cards, bursts of excitement with Daniel which never come to anything. Then read on to see that the feel-good factor has been replaced with the "Sod it - oh, Christ" syndrome.

I don't know why they bother with all that time-consuming, costly research. They should just save themselves a lot of money and ring me up.