But now technology, in the form of a coded microchip, is about to make the ringer - a horse deliberately or accidentally masquerading as another - an extinct species.
Intentional substitutions have long been part and parcel of the darker side of racing's colourful history, but are (at least those to have been discovered) relatively rare. Mistaken identities - of which there have been several lately - are potentially more embarrassing and damaging to the sport's integrity in the modern era.
But from next year every thoroughbred foal registered in Britain and Ireland will have an individually-numbered microchip implanted in its neck as a lifelong failsafe means of identification. A special hand-held device can read the microchip code in a matter of seconds, which means every horse can be checked instantly, not only on arrival at the race track but also in the parade ring.
At present thoroughbreds in Britain are identified on racecourses by means of their colour, white markings and whorls (patterns of hair growth) indicated on an outline drawing on their passports, an accurate but not absolutely infallible method and time-consuming to check in every case.
Earlier this year a juvenile filly, Oriel Star, ran twice as Slightly Dusty after the pair, both from David Evans' yard at Leighton, on the Welsh border, had become mixed up as yearlings.
In August, Jack Berry's two-year-old Perigeux mistakenly ran as his three- year-old stablemate Royal Dream. Two years ago Reg Hollinshead's Loch Style ran as Taniyar at Southwell, and in 1995 Ela-Ment, trained at Limpsfield in Surrey by Brian Pearce, ran twice as Hong Kong Venture.
Weatherbys, the body responsible for the registration of horses, started trials last year after several years' monitoring in other countries. Microchips are already extensively used on trotting horses in Europe and in farther- flung places like Saudi Arabia and Thailand.
South Africa is soon to adopt the system; the authorities in America, where racehorses have a number tattoed on the lip before they go into training, are keeping a watching brief.
The chip itself is about the size of a grain of rice and is embedded around two inches deep in the large nuchal ligament above the vertabrae of the neck on the left-hand side. The procedure, no more painful or complicated than an injection, will be carried out by veterinary surgeons at the same time that the foal is blood-typed and has his or her markings recorded.
Hamish Anderson, stud book director at Weatherbys, said: ``Ours will be the first mainstream thoroughbred population to use microchipping. It is quick and easy to do, and quick and easy to utilise, and will be to the benefit of everyone involved, from breeder to punter.''
The British Horseracing Board and the Irish Turf Club are to fund the cost of the microchips, which will be bulk purchased to keep costs down. Numbers are likely to be in excess of 12,000 and vets estimate a cost of around pounds 10 for an implantation.
But security and integrity in racing apart, there are other benefits from a permanent identification record for each thoroughbred. Those that leave the confines of the racing world will still be traceable, whether they go on to perform in other sports or indeed fall on hard times.
Anderson said: ``Those that go eventing or showjumping often lose their identities and appear under another name. And microchipping will enable ex-racehorses which have been neglected to be properly identified.''
The microchip will also be a valuable tool in an area where there are serious implications for equine welfare because of Brussels bureaucracy. There is currently a move (being strongly resisted by British and Irish vets) within the European Union to prevent the use of drugs - even painkillers used on humane grounds - on horses because on the Continent equines, many purpose-bred, are a legitimate part of the menu.
Anderson said: ``The idea of not being able to treat a horse in pain with drugs is apalling, but there is a real danger of it happening. The reason is that the minimal residual levels of drugs are not all known and so all will be banned to avoid danger to those who might consume the horse. Our argument is that a microchipped horse is one that can be permanently identified and therefore definitely kept out of the human food chain.''Reuse content