Despite an epic victory in the Prix de l'Arc de Triomphe at Longchamp, Sea The Stars is not the greatest horse in history, according to Timeform.

The Halifax-based firm had already identified Sea The Stars as “one of the best of all time” going into Europe's all-aged middle-distance showpiece.

Though he brilliantly came from off the pace to beat Youmzain by two lengths, the John Oxx-trained colt did not do enough to improve his mark of 140, argues Timeform handicapper Chris Williams.

The three-year-old was already firmly established among racing's pantheon of immortals before the race and his mark ranks alongside those of Dancing Brave and Shergar — but he is not regarded as good as Sea Bird II (145), Brigadier Gerard (144), Ribot (142) or Mill Reef (141).

Williams said: “While it was a difficult race to assess, we can't justify putting up Sea The Stars higher than 140. The bare form was not as good as in some of his other efforts. He was very impressive but he beat Youmzain by a couple of lengths, which is really all Zarkava did last year.”

Phil Smith, head of handicapping at the British Horseracing Association, agreed. He believes Sea The Stars ran to a mark of 131, four pounds below the rating he achieved when winning the Irish Champion Stakes on his previous run.

“Every time you put opposition in front of him he beats them and is an absolute tip-top horse,” Smith said.

“But we've left him on 135, which was the mark we had him performing to in the Irish Champion Stakes.”

In showing his great turn of foot under Mick Kinane, sealing his sixth Group One in as many months, Sea The Stars became the first horse to win the 2,000 Guineas, Derby and Arc.

Though he is an odds-on favourite for next month's Breeders' Cup Classic, the Christopher Tsui-owned colt's stud value is already at an estimated £50million and it will be a surprise if he runs at Santa Anita.

“We'll let the dust settle and have a think about it and we're not ruling it out,” said Oxx. “We're not going to rush into a decision and we'll have a discussion about it.”