By Cornelius Lysaght BBC racing correspondent

Aidan O'Brien may be the king of Flat racing, but he might have to shift over on his throne at Ascot this weekend.

On Saturday, the course's Queen Elizabeth II Stakes day - the lady herself can grab some headlines with the help of a two-year-old young filly named Golden Stream.

The winner of an above-average Newmarket fillies' maiden on her only start, she is being aimed now at the 2009 Epsom Oaks, via Ascot's Group One Meon Valley Stud Fillies' Mile (1505 BST).

And Golden Stream, who would follow the Queen's horses Carrozza (1957) and Dunfermline (1977) if successful at Epsom, is one of a string of horses that have carried the Royal silks through a season that can happily be described as an annus mirabilis.

Free Agent has been one of the Queen's winning racehorses

So far this year, horses owned and bred by the Queen have won a dozen races from 60-odd starts, and what has been so striking is the success of the youngsters.

As well as the Michael Stoute-trained Golden Stream, it would be no big surprise if three other two-year olds, Four Winds, Free Agent and Full Toss all made next year's Classic races.

All are prodigious talents, and Four Winds could be very interesting in October's Racing Post Trophy, but Free Agent will stick in many minds following this year's Royal Ascot.

Success in the Chesham Stakes for the colt, trained by Richard Hannon, sparked off scenes of celebration to melt the heart of even the most ardent of republicans.

The owner/breeder positively radiated delight at the impressive performance which had Hannon, not one renowned for talking up his geese as swans, to identify the 2009 Derby as a reasonable target.

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Aureole, ridden by Harry Carr in coronation year (1953), came closest, but he was still four lengths adrift as jockey Sir Gordon Richards finally tasted Derby success on Pinza.

And, although some might hurl anti-monarchist brickbats, victory in the race for the Queen would be a massive moment for the sport as well as for her.

The centuries-old Royal patronage of racing is crucially important.

As well as providing a popular figurehead for those involved, the Queen's presence is also a significant part of the reason that British racing is so renowned around the world.

Additionally, the brand �Royal Ascot' is, of course, one of the best-known in global sport, and she clearly plays a pivotal role in all that. So, racing as whole will be watching the progress of her Classic hopes with considerable interest.