Racing: Marling to exploit her rivals' weight of years: Paul Hayward picks the filly in today's mile championship

NOT ONLY is Marling a rival to St Jovite for the title of 1992's leading three-year-old. The remarkable physical detail about the Irish 1,000 Guineas winner is that she is defying the theoretically inevitable onset of middle-age spread and is currently racing 20lb leaner than she was last season. Her secret would be worth a fortune in Surbiton diet centres.

In the fuss over St Jovite it is easy to forget that Marling has been beaten just once in seven races and that her sole defeat, in the 1,000 Guineas, was the unluckiest in a Classic since Dancing Brave rocketed fruitlessly down Epsom's straight in the 1986 Derby. Still, six victories, three Group 1 races and pounds 398,650 are ample advertisements for the benefits of slimness.

They also place Marling (3.10) in the deserved position of favourite for this afternoon's Sussex Stakes, which, despite the unerring quality of its winners, has been without a sponsor for the past three seasons. Any race that can include Chief Singer, Rousillon, Sonic Lady, Warning and Zilzal among its last 10 winners ought to attract some kind of corporate interest.

The bookmakers say Marling will start at about 5-4 today because many big-time punters see her as the banker of this year's Glorious Goodwood. 'It's the first time she's tackled the colts and the older horses,' Geoff Wragg, her trainer, said yesterday, 'so we'll see tomorrow whether or not she's good enough.' Asked if he thought several of the senior contenders are potentially flawed, Wragg said, 'they all look pretty good to me.'

But Newmarket's chattering classes have long maintained that Marling will dispose of Second Set, Sheikh Albadou - winner of the Breeders' Cup Sprint - and Selkirk, last year's champion miler. They were saying so in loud terms during their July meeting a fortnight ago. Against Second Set - last night the subject of worrying rumours concerning an abscess in his mouth - is the fact that no horse has won the race twice, while Sheikh Albadou's stamina may fail and the vibes for Selkirk are not good (Sikeston needs soft ground and the rest lack the necessary brilliance).

In Marling's favour is the fact that, as in the King George, three-year-olds have the better record, partly owing to the weight-carrying terms of the race (the favourite will bear 11lb less than Selkirk and company this afternoon). Wragg chose the Sussex in preference to the July Cup, and knows that Marling's days of kicking aside her contemporaries are over. 'Sooner or later you've got to take the bull by the horns and take on older horses,' Wragg says.

Winning the Richmond Stakes, in contrast, can be the worst thing that can happen to a promising juvenile because the majority of the last 10 winners have disappeared down racing's obscurity tunnel. Darbonne (3.45) ought to reap a few more successes before the uncertainty of winter sets in, while Farsi (next best 2.30) and QUICK RANSOM (nap 4.15) are two for handicap addicts. They do exist.