All grey thoroughbred horses are supposedly descended from the Alcock Arabian, an Arabian stallion of indefinite origin, but probably imported, via Constantinople, by Sir Robert Sutton, English Ambassador to the Porte, in the early eighteenth century. Certainly, grey horses are a rarity, representing about 3% of the thoroughbred population in Britain.

Grey colouring is determined by a dominant gene which, if inherited from a parent, is expressed, over other colour genes, in coat colour. In other words, all grey thoroughbred horses have at least one grey parent. Grey horses are usually born black, brown or chestnut, but gradually grow lighter in colour, to become dappled, grey or white.

In later life, most grey horses develop dark-pigmented tumours, called melanoma, on their skin, but these are mostly benign and require little or no treatment. However, influential Italian breeder Fedrico Tesio insisted that grey horses were ‘diseased’, leading to them falling out of favour. Nevertheless, it’s the scarcity of grey horses, coupled with the fact that they’re easy to spot, which has led to their enduring appeal in horse racing circles.

As far as the Grand National is concerned, in 179 years since the inaugural running of the Grand Liverpool Steeplechase, as the race was originally known, just three grey horses have won. One crackpot theory suggests that grey horses have fared poorly at Aintree because they’re more susceptible to the vagaries of the Merseyside weather in early April than horses of other colours. Anyone who subscribes to that theory, though, would do well to remember that Desert Orchid – possibly the most popular grey in the history of British horse racing – enjoyed his finest hour, in the Cheltenham Gold Cup, on a foul, rainy day when racing only went ahead after a midday inspection.

Of course, Desert Orchid never ran in the Grand National – although he did win the Irish equivalent at Fairyhouse the year after his Gold Cup triumph – but the roll of honour at Aintree does include The Lamb (1868 and 1871), Nicolaus Silver (1961) and Neptune Collonges (2012).

Owned by William Henry, sixth Earl Poulett, The Lamb stood less than 15½ hands high – about the same height as the 2018 Grand National winner, Tiger Roll, who was affectionately described by his owner, Michael O’Leary, as ‘a little rat of a thing’ – and was apparently so named because of his diminutive size and placid nature. He had the distinction of winning his first National as a 6-year-old, under amateur jockey George Ede, in 1868 and, having subsequently contracted an illness that kept him off the course for two years, won his second as a 9-year-old, under another amateur jockey, Tommy Pickernell, in 1871. Mysteriously, some paintings and sketches depict The Lamb not as a grey, but as a black horse.

The second grey to win the Grand National, Nicolaus Silver in 1961, was unmistakably grey, in fact, almost white, with a hint of dapple on his quarters and legs. He was bought, for £2,600, by Kinnersley trainer Fred Rimmell, on behalf of owner Charles Vaughan, following the sudden death of his previous trainer in 1960. The following spring, Nicolaus Silver lined up at Aintree as an unheralded 28/1 chance but, relishing the firm ground, drew clear in the closing stages to beat the previous year’s winner, Merryman II, by 5 lengths.

The third and, so far, final grey to win the Grand National was Neptune Collonges, trained by Paul Nicholls and ridden by Daryl Jacob, in 2012. Classy enough to complete a Nicholls’ 1-2-3, behind Denman and Kauto Star, in the Cheltenham Gold Cup in his younger days, Neptune Collonges was, by now, a doughty 11-year-old, whose coat had grown even lighter with age. Nevertheless, he became the first horse since Red Rum to carry 11st 6lb or more to victory in the National and his winning margin, a nose, was the narrowest in the history of the celebrated steeplechase.