It was well worth the wait - and the anxious few days - as Kingston Hill finally had his moment of glory in the Ladbrokes St Leger at Doncaster.

All week the "will he, won't he run?" debate because of the ground potentially not being soft enough kept the favourite's supporters on tenterhooks.

But connections took the plunge and the gamble paid off as the Derby runner-up landed the final Classic of the season.

Providing jockey Andrea Atzeni and trainer Roger Varian with first domestic Classic victories, Kingston Hill was returning in triumph to the scene of his Group One success in the Racing Post Trophy in October.

Punters kept faith with the horse, sending him off the 9-4 favourite, and just as Epsom third Romsdal moved to strike for Leger specialist John Gosden, he began his charge.

Although he brushed past eventual third Snow Sky, forcing a brief stewards' inquiry, he was a length-and-a-quarter on top at the post.

No horse had more left than Kingston Hill, who has run in all three colts' Classics, having started his year off with an eighth in the 2000 Guineas, but was making his first appearance since finishing fourth in the Eclipse at the start of July.

Varian said: "I can't put it into words. It's brilliant, it's a relief and exciting. It's an exciting thing to win a Classic and it's what we're all in it for. It's great for the horse. We've had a bit of heartache with him through the year. He came good on the day and Andrea gave him a brilliant ride.

"The plan was always to come with a long run down the outside as he's not a horse who quickens instantly. He's got a big, long stride and a long straight like this is ideal. I was a bit worried three out as I thought we might have a bit too much ground to cover, but he stayed on well and shown his class.

"I'm delighted for the horse to win a Group One this year. He looked a Classic horse at the start of the year and he's won a Classic. I think the long nights and the dew have helped with the ground, and also today being overcast, but I think it was quicker than ideal for him.

"First we have to get him home and see if he comes out of the race OK. He's not had a busy summer. Hopefully he's not finished this year.

"We'd have to consider the Arc if he has come out of this OK. He's had a hard race. He's got out to come of it well and we have to make sure he's 100%. I think he deserves his chance."

Atzeni said: "I don't know what to say, it's a dream really. It's unbelievable. I rode him like the best horse in the race, he travelled beautifully. He's so laid-back, he goes to sleep. When I pulled him out he was always going to get there. He was just wandering about when he hit the front."

Winning owner Paul Smith admitted being in tears, with more likely to come. "It hasn't sunk it yet," he said. "There will be a few tears tonight. There have been some already. It was nerve-wracking. It's a huge race. My dad [Derrick Smith] and Mike [Dillon, of Ladbrokes] have put a lot into it and it's just great to be here.

"He's been a bit unlucky with the ground this year, but we wanted to run him and he handled the ground fine. Andrea got one clean run with him on the outside and once he gets rolling he's mighty hard to get past."

Gosden, who had three runners in the race headed by Romsdal, said: "Romsdal finished his race really well and he was closer to the winner than he was when they met in the Derby."

Sir Michael Stoute felt Snow Sky had failed to see out the trip. He said: "I was pleased with Snow Sky, but to be honest I didn't think he quite got home and he'll be sticking to a mile-and-a-half in future. The other horse [Kings Fete, who was ninth] definitely didn't stay."

Richard Hannon, trainer of the fourth home Windshear, said: "All he has done this year is grow and get stronger, so next year will be a big year for him."

There was drama before the start when Odeon was not allowed to run, as he was still wearing headgear he was only supposed to wear in the paddock.