THE market did not act rationally in shortening Blaklion’s odds for the Grand National on the back of his Becher Chase win at Aintree last Saturday. Paradoxically perhaps, Nigel Twiston-Davies’ horse’s chances of winning the Aintree Grand National were probably reduced on the back of Saturday’s win, not enhanced.

Bookmakers love to shorten a winner. Regardless of how impressive or otherwise a horse is in victory, or no matter how little he achieves, a win usually results in the tightening of the odds on any potential ante post target that the horse may have.

And so it was on Saturday with Blaklion. Available at 16/1 generally for the Grand National early last week, he was cut across the board after Saturday’s win, to 10/1 generally and 12/1 in places.

He was impressive in winning on Saturday, no question. He jumped the big fences well, he travelled through his race well for Gavin Sheehan, he made his ground through his field nicely and he won easily.

But, in so doing, he was achieving no more than he was entitled to achieve. As mentioned last week, the handicapper had dropped him, somewhat bizarrely, by 2lb for his Charlie Hall Chase run, when he recorded the highest Timeform rating of his career in going down by a half a length to Bristol De Mai, who is now rated 14lb higher than he was then.

So Blaklion looked like a seriously well-handicapped horse going into Saturday’s race. That is why he was sent off as the 7/4 favourite.

And we already knew before Saturday that he could operate around Aintree. He jumped the big fences really well in last season’s Grand National.

Nigel Twiston-Davies and the owners had a decision to make: (a) go for the Becher Chase, for the £80,000 or so first prize, which they had a serious chance of winning with a horse who was fit and well and ready to run, and take your chances in the Grand National in April off an inevitably higher mark, or (b) spurn the Becher Chase, and every other race between now and the publication of the Grand National weights in the middle of February, and retain your handicap rating of 153 that would optimise your chance of winning the National.

Either course of action was a legitimate course, and they obviously decided on the former. Bird in the hand.

The net result is that Blaklion’s handicap rating has been raised by 8lb to a mark of 161, and that makes a National tilt more difficult than it would have been.

Any logarithmic suppression of handicap ratings at the top of the handicap will probably be counteracted by the Aintree factor for Blaklion, by his exemplary record over the big fences (fourth in a Grand National, first in a Becher Chase), so his National mark should be close enough to his actual handicap mark.

Racing off a mark of 161, he would be 9lb higher than the mark off which he raced last year when he finished fourth. Not that he can’t win it off that mark, because he can, he should be better equipped for the race this season as a nine-year-old than he was last season as an eight-year-old.

When Hedgehunter won it as a nine-year-old in 2005 after falling at the last as an eight-year-old the previous season, he was racing off a mark that was just 3lb higher than his 2004 mark. But he won easily, by 14 lengths. It is probable that he would have won it even with 6lb more on his back.

However, if Blaklion’s connections had chosen option (b) above, he could have been set to race off a mark of 153 in April, all going well, just 1lb higher than last season’s mark.

Therefore, his chance of winning the Grand National has not improved on the back of Saturday’s win. His Grand National odds should not have been shortened. Indeed, you can argue that they should have been lengthened.