JOES EDGE (3.15) has the potential to spring one of the biggest upsets of all time in this afternoon's £400,000 Cheltenham Gold Cup.

I'll probably end up with egg over my face judged by his crazy odds of 150-1, however he owes followers of this column not a penny having landed a 25-1 nap by winning the 2005 Scottish Grand National.

Seven days ago as the rain lashed down over the Cotswolds the flags were all half-mast at Ferdy Murphy's camp, reflecting the rapidly declining prospects of Joes Edge.

But as Harold Wilson once famously said: "A week is a long time in politics," a scenario which applies equally to horse racing because the ground has dried up significantly since then.

Quickening underfoot conditions are not going to suit many of the market principals, whereas Joes Edge loves to hear his hooves rattle, plus has a record of coming good at this time of year

For those of little faith, it's well worth recalling the totally unfancied Norton's Coin was the 100-1 winner of the Blue Riband contest in 1990, which just goes to show huge shocks do occur at the Festival.

Neither would be it wise to forget that Ferdy has already bagged a spanking brace of 33-1 scorers at the meeting so far, You're Special and Hot Weld, confirming the fantastic form of his West Witton in Wensleydale yard.

The opening JCB Triumph Hurdle has been the target all season for Afsoun (2.00), who served notice of his future intent by notching a track and trip success much earlier on this term.

Mick FitzGerald's mount was also massively impressive on his prep outing more recently at Huntingdon, quickening clear for a bloodless victory and prompting a flood of ante-post on the classy four-year-old.

Although there was a slight scare about Afsoun's state of health last week, all appears hunky-dory now. "He's fine and I wouldn't run him unless he was 100% right," explained trainer, Nicky Henderson.

Black Jack Ketchum (2.35) puts his unbeaten record on the line in the Brit Insurance Novices' Hurdle.

Jonjo O'Neill's star hasn't put a foot wrong during the past 12 months, and it'll be no surprise if he justifies his short price as market leader for the £75,000 three-miler.

At the other end of the betting spectrum, Liberty Seeker (4.40) will likely go off at any price you like for the Grand Annual Challenge Cup.

Liberty Seeker began life with Mick Channon, then went to Alan Swinbank, followed by spells with Peter Niven, Peter Monteith, and Ian Semple, prior to returning to team Swinbank.

For a horse whose had more clubs than Jack Nicklaus, Liberty Seeker retains tons of ability and didn't perform at all badly on his Musselburgh comeback in February.

The selection is a total two mile specialist, will get every assistance from Davy Russell in the saddle, and therefore couldn't be discounted for what is another wide-open event.

In keeping with tradition, the Vincent O'Brien County Hurdle brings the curtain down on National Hunt's premier fixture of the year.

With the maximum allowed field of 30 runners facing the starter, it's a minefield for punters and as ever there are bound to be a plethora of hard-luck stories.

It goes without saying that steering clear of trouble is paramount and few are better at threading their way though the pack than Ruby Walsh, who partners Desert Quest (5.20) in the finale.

Like Joes Edge, Desert Edge relishes a fast surface, a point underlined in no uncertain manner when the Paul Nicholls-trained gelding won with his head in his chest at Newbury last time out.

It was a clever piece of placing by Nicholls, since his horse has only been penalised a measly 4lbs for that cosy win, not nearly sufficient in my view to prevent him taking a hand in the finish.

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