Yorkshire racecourses have been as important to top class racing this season as Mo Farah was to the Olympics.

With the memory of Frankel, trouncing his rivals at York, still fresh in the memory, all eyes are on Doncaster this afternoon for the St Leger.

The oldest Classic in Britain has always a story behind it and this year is even more special with Camelot bidding to land the Triple Crown, the first horse do so since Nijinsky in 1970.

Camelot has not run since winning the Dubai Duty Free Irish Derby at the Curragh, purposely being given a break with history in mind by his trainer Aidan O'Brien and his powerful Coolmore owners.

It also promises to be a landmark day for O'Brien from another point of view, as victory in the Leger would mean he would become the first to train all five British Classic winners in a single season.

Aside from Camelot, the O'Brien-trained Homecoming Queen won the 1000 Guineas while Was landed the Investec Oaks.

O'Brien said: "We've had great horses all through the years and you always hope something different will come along again and then when Camelot arrived it was just incredible.

"He's an incredible talent really. One of those very special horses, one that only comes once in a lifetime.

"I thought it (winning the 2000 Guineas) was impossible really, I have to take my hat off to the lads for trying it.

"He went there doing half-speeds and the lads were prepared to let him go there, it was a big call and he had an awful lot to lose. It was one of those special days.

"In the Irish Derby I was very worried as everything was against him - the ground and he hadn't worked on grass since Epsom, so he hadn't done a lot of work in that kind of ground.

"We gave him a good break and his weight started to increase, which was unusual. He will be heavier for the Leger than he has been going into any other race but with three-year-olds they often don't change until later in the year.

"His body is built more like a miler in that he is round and strong as opposed to angular and lean. That is a little thing that would be in your mind.

"We are in the zone where you don't want to talk about things - you just want to keep everything smooth.

"We think Camelot is like no other horse. Who knows what is going to happen? - we don't take anything for granted. We will do our very best - it's all we can do."

Camelot, a son of Montjeu, will be going into the unknown trip-wise, with O'Brien conceding it is the ultimate test.

He said: "We (O'Brien and his wife Annemarie) breed horses - you don't look for just speed anymore, it is class you look for (in stallions).

"They have to have speed, stamina and courage - they are the three most important things when you are breeding horses. The Leger will expose the last two.

"To be going for the Triple Crown is something I could never dream of happening. Extreme distance can break hearts. The Triple Crown is the full test of the three-year-old.

"We've had great horses all through the years and you always hope something different will come along again and then when he (Camelot) arrived it was just incredible. He's an incredible talent really. One of those very special horses, one that only comes once in a lifetime."

And to top it all off the trainer's 19-year-old son Joseph takes the ride again. However, looking at a betting angle, Camelot is going to go off around 1-3 favourite and with nine runners in the field it looks a decent each-way race to bet on rather than back the favourite.

A very interesting runner with untapped potential is the William Haggas-trained Guarantee, who gives Thirsk jockey Philip Main his first ride in a Classic.

Coming through the handicap ranks, Guarantee is 2-2 under Makin, with polished displays at Ripon and a very smart performance in the Melrose Stakes at York.

Haggas said: "He's very well and will have enjoyed the rain that came on Wednesday. He's an improving young horse, but he's got another huge mountain to climb.

"He's really going the right way, he's on good terms with himself and if you're not in, you can't win."

At around 16-1 I think he makes plenty of appeal each-way, in a race that can't be missed for numerous reasons.