The silver-haired, comfortably padded Jenny Pitman might look like a grandmother, but in the hard world of horseracing she's a legend. She was the first woman to receive a training licence from the British Jockey Club, she's won the Grand National twice, as well as dozens of other major races, and she was awarded an OBE in 1998. She's also notorious for her toughness - once giving a jockey a smack across the face for hampering one of her horses in a race.

In 1997, after she was diagnosed with cancer, Pitman retired from racing and took up writing. Her autobiography was published in 1998, followed by her first novel, On The Edge, last year. Both were best-sellers. Her heroine, Jan Hardy, is, by all accounts, based on Pitman. Hardy is a tough, talented and ruthlessly honest woman who teaches the boys a thing or two. Pitman's second novel, Double Deal, was published a few months later and continued the saga of the indomitable Jan, this time exposing corruption in horseracing. The Dilemma is the third novel in the series, and the plot is wearing desperately thin.

Hardy old Jan returns with a new hairdo - blonde and tousled - and a string of problems. She has lost seven horses from her stable, her boyfriend has got another woman pregnant, and her mother-in-law has been poisoned. The dilemma of the title is difficult to define. She does have two men in her life - boring-but-stable doctor Tony, and dashing-but-unreliable art dealer Eddie. But Hardy makes it clear from the beginning which she prefers: dashing Eddie, obviously. And even though Eddie dumps her, she won't give Tony a chance. No real story there.

The rest of the book is about going to horse shows, buying horses and watching races: this one looks strong, that one has straight legs, this one's got good breeding, ground's got a bit of give in it today ... If it sounds boring, that's because it is.

It's not that there's anything wrong with the subject matter, as Dick Francis and John Francome have shown. But Pitman's more interested in weighing up the pros and cons of Jan's existing and prospective boyfriends than spending time with the ponies.

There aren't even any guilty pleasures here. No sweaty sex in the haystacks or Jilly Cooper-style ripping jodhpurs. Then again, how many people want to read about steamy sexual encounters between middle-aged horse trainers?

The worst thing about this novel is the tediously expository dialogue. Try this: 'Jan nodded, 'Poor Mum, I wonder how she found out. She really wanted me to get together with Tony, the doctor who was so kind when Matty was ill last year.'

'I remember - steady reliable sort of a guy.'

'That's him.'

'Whereas she thinks this Eddie's a bit of a Romeo and about as much use as an ashtray on a motorbike.''

Pitman's had a good run with her first two novels. Now she should take a tip from the world of horseracing and quit while she's ahead.