TOP hats and morning suits will be dusted down today as the racing world prepares for tomorrow's local equivalent of the Epsom or Kentucky Derbys. The International Cup is Hongkong's race of the season and one of the most heavily backed in the world. Millions of dollars will be riding on the thoroughbred backs of equine athletes from Britain, the United States, Australia, Canada and Japan as they all look to beat local favourite, River Verdon. Thousands of words have been written about their chances, their jockeys, their trainers. Punters will be drooling over the form books right up to ''the off''. But one man who never rates a mention is Giles Instone, the racing world's Pegasus. His company ships thousands of horses around the world every year. Just how well they have travelled could have a bearing on who is led into the winner's enclosure. For some what will amount to less than two minutes on the track will have involved over 24 hours standing in a horse stall in the belly of a claustrophobic cargo plane. For a human a flight half that length in comfortable seating can take its toll. ''Horses are like human beings in that some travel better than others,'' said Mr Instone who will be watching the big race from the Sha Tin stands tomorrow. ''We have had no problems with the horses we have shipped this year, although a couple may have had a temperature for one or two days.'' Preparations to ship horses overseas start three weeks beforehand with blood tests. ''The idea is to see that the horses are not carrying any diseases which are not welcome in the importing country,'' said Mr Instone. Once on the plane, which has to be strictly temperature controlled, a series of professional flying grooms are in constant attendance. The ratio can be as high as one man per horse. ''Their job is to fly around the world with horses. They are highly-experienced in the use of drugs and veterinary first aid,'' said Mr Instone. After a long flight enough time is always allowed for the horse to recover before the race. The whole transportation procedure is much more sophisticated and more comfortable for the horses than it was a few years ago. One major reason for this is the introduction of wide-bodied aircraft, said Mr Instone. Another is the quality of the horse-carrying equipment which Instone Air Services have pioneered. They are shortly to introduce a sealed, insect-proof airstable which will slash hours off travel time. At the moment a flight to Australia, to meet the approval of the Australian Quarantine and Inspection Services (AQIS), goes from Britain via Canada, Hawaii, Fiji, and New Zealand and takes up to 36 hours. But because the sealed boxes mean disease-carrying mosquitoes do not come into contact with the horses, the animals can travel on scheduled services on shorter, more direct routes. Up until 1976 Mr Instone ran a trucking company specialising in moving film scenery and outsize loads. When he heard from a friend that only one airline was carrying horses because it was the only one with horse stalls, he set about capitalising on the market, making and supplying equipment to airlines. Instones is the leading supplier of horse equipment in the world and among the top horse forwarders. The company ships around 3,000 horses a year of which Cathay Pacific carries around 500. ''Cathay Pacific is the Rolls-Royce of animal carriers in Asia,'' said Mr Instone. Instones also carry show jumpers and polo ponies. They are the world's largest shippers of cattle by air. And just to prove that pigs can fly, Instone ships thousands of them. Indeed, nothing is too big or too small for this company, be it llamas from Chile, white tigers from Las Vegas, elephants, killer whales or importing venereal disease-free camels from Australia into the Middle East. ''Shipping race horses after all that, is very easy,'' said Mr Instone.