A maximum field of 30 have been declared for Saturday's Scottish National at Ayr (3.25) with Neptune Collonges' presence at the top of the weights meaning all bar eight horses will run from out of the handicap.

There was a similar scenario three years ago and we got a real shock result in Iris De Balme, who won from 26lb out of the handicap at 66/1. With three other winners being sent off at 20/1 or bigger in the past decade, it's safe to say this is a race in which you should expect the unexpected and favourite backers in particular have suffered with no market leader obliging since 2000. All of which makes me view this year's market principals with a certain degree of scepticism.

Take this year's jolly Chicago Grey. On paper, he looks to have the perfect credentials as he stays all day, has a very attractive racing weight of 10st 9lb, won't mind the ground and will be ably ridden by Paul Carberry. However, I'd be worried about the hard race he endured when winning the four miler at Cheltenham last time and he wouldn't be the first horse to fail to follow up here; most recently Poker De Sivola (pulled up), Old Benny (fourth) and Native Emperor (pulled up). Besides, he's no certainty to beat the Cheltenham second, Beshabar, who is 5lb better off for a four-and-a-half length defeat. His price of 5/1 is an even bigger turn off.

This has not been a great race for Paul Nicholls in recent years but he does control the weights this time with Neptune Collonges and his stablemate The Minack looks to be sitting pretty on 10st 1lb with Ruby Walsh penned in next to his name. He has stamina to prove but his breeding is encouraging in that respect as he's out of that grand staying mare Ebony Jane. However, having watched the video of his Reynoldstown third (would have finished second but for a bad mistake), I'm far from convinced he jumps well enough to win this and he too is readily passed over at the odds.

Not so easy to pass over is POKER DE SIVOLA, who looks to have had an ideal preparation, in stark contrast to 12 months ago when he arrived here on the back of winning the four miler. That race had clearly taken it's toll and connections have deliberately kept him fresh this time restricting his campaign to just two races, the latest of which was a never threatening sixth in the Cross Country Chase at Cheltenham. That speed test was never going to suit him and he will find this regular park course, off what should be a strong pace, much more to his liking. The negative is that he's 6lb 'wrong' at the weights but that is more than compensated by his price of 16/1 and it's worth noting that his stable's two winners of this race in the last decade were relatively unfancied at 14/1 and 20/1.

If we are going to get a real shock winner of the race this time, it could be provided by COLD MOUNTAIN, who is a whopping 100/1 with Stan James, who are also paying out down to five places. That could prove highly generous as the nine-year-old is an out-and-stayer, having won over 4m2f at Taunton last time, and will love the drying ground. This is much tougher of course and he's miles out of the handicap but past results show it can be done and he will be staying on when others have cried enough. He surely won't be 100/1 when the tapes go up.

At the time of writing, both Fair Along and Bellflower Boy are classed as doubtful runners, so the field could be reduced to 28.

Betting Advice: Back Poker De Sivola and Cold Mountain each-way