The Investec-sponsored Derby at Epsom, with the colts scheduled to leave the gates for this simulcast spectacular at 11pm on Saturday, has caused one of the biggest divides in modern British racing history and the issue is simple: are you for or against Australia?

Those screaming for this gorgeous-looking colt remind us firstly that he was bred for this very job. He is sired by Derby winner Galileo, out of an Oaks winner (the Epsom fillies' Classic over the very same distance) by the name of Ouija Board who was the runaway winner of the Hong Kong Vase back in 2005.

Moreover Australia's trainer Aidan O'Brien who has won Britain's most famous race four times- including for the past two years – has consistently described this colt as potentially the very best his champion Irish stable has ever had contained.

Only third in the 2000 Guineas (1600m) at Newmarket last month but his supporters argue that both distance and the way that Classic race was run conspired massively against Australia's talents, and anyway some of its contenders have since produced some fabulous performances.

Supporters also point to incredible homework, with Australia apparently producing remarkable fractions on the gallops that suggest he might be fast enough to win Group 1 sprints were he ever allowed to compete in them.

Australia's detractors – some suggesting that he is overhyped and has underachieved - use the same argument reckoning that it is impossible that a colt this fast – whatever his breeding – can be as potent over the 2409m of Saturday's great British Classic run on Epsom's uniquely difficult course.

Then there is Saturday's super-strong opposition that includes winners of numerous Epsom Derby trials comprising Australia's stablemates Orchestra and Kingfisher, along with fellow Irish challenger Fascinating Rock and the unbeaten Western Hymn.

And what about Geoffrey Chaucer, another stablemate and rumoured also to be burning up the gallops at Ballydoyle.

Then there is Kingston Hill whose big following has grown bigger with the prospects of soft ground on Saturday, and let's not forget Arod and True Story - both of whose chances appear much stronger since their York conqueror The Grey Gatsby's destruction of the cream of French three-year-old's in last Sunday's Prix du Jockey Club at Chantilly.

Given all this excited debate, supporters of Australia must be delighted to hear the words of his jockey Joseph O'Brien, son of the trainer, who insists: “I just don't suffer from pressure. In fact I thrive on it.”

Five other fascinating races on Saturday's programme include the Investec “Dash” over the world's fastest 1000m and the Investec Coronation Cup – a Group 1 spectacular for older horses over the Derby distance.

In this event the popular and extraordinary French-trained eight-year-old Cirrus Des Aigles, brilliant winner of two Longchamp Group 1's since running third in last December's G1 LONGINES Hong Kong Cup (2000m), will have a legion of followers screaming him home under jockey Christophe Soumillon.