Although the richest horse in the world emerged from the USA, plenty of racehorses earned incredible money during their careers while trained in the UK.

Still, the UK races usually aren't that rich; therefore, if anybody wants to attack the global leaderboard, they must point their horses abroad, especially to the US, United Arab Emirates, Saudi Arabia, Japan, and possibly France due to the Prix de l'Arc de Triomphe. In the case of sticking just to the UK, it's practically impossible for a horse to join the ranks of the world's richest horses, as the wealthiest race there is the Epsom Derby. And a horse can run it only once in their lifetime – when they are three years old.

1. Thunder Snow, £12,671,800

The bay horse was born in Ireland in 2014, and despite the current trend of running the best horses for only a couple of years, Thunder Snow remained on track for four seasons. Thanks to his owners, the Godolphin, he was allowed to attack the leaderboard of the richest horses in 24 starts, and currently, he is in second place, bettered only by the might Arrogate from the USA. Thunder Snow showed lots of talent as a two-year-old when winning the G1 Criterium International in France, upon which trainer Saeed bin Suroor experienced a roller-coaster-like season in 2017 with him.

Thunder Snow scored two Classic races in the UAE and earned a spot in the Kentucky Derby, where he could've been a dark horse. However, Christophe Soumillon aboard couldn't persuade his mount to run as Thunder Snow bucked right after the start and didn't finish the race. Nevertheless, the horse made amends in his four following starts, scoring another G1 in France. Later, he returned to Dubai, where Thunder Snow proved to be the best horse in the field for the Dubai World Cup 2018, winning easily.

Moreover, he delivered a solid run in the Breeders' Cup Classic at the end of the season when finishing third, and in 2019, he became the first horse ever to win the Dubai World Cup for the second time. Everybody, even the best horse racing bookies on GG watched his second triumph with batted breath. Thanks to his consistent performances, Thunder Snow is still the richest horse trained in the UK ever. 

The John and Thady Gosden-trained horse was also born in Ireland but raced for the UK throughout his career, which consisted of 21 outings. Firstly, Mishriff scored in the French Derby in 2020, but his richest victory occurred in Saudi Arabia in 2021. Under David Egan, Mishriff switched to the dirt track without any issues, bettering the US stars and triumphing by a length. The Saudi Cup is the wealthiest race in the world; therefore, Mishriff immediately skyrocketed to the top spots on the global leaderboard. 

He settled in third place after he added prize money from his victories in the Dubai Sheema Classic from the UAE and Juddmonte International in York. Still, recently, Japanese Usha Tesoro skipped him. Currently, Mishriff is the fourth richest horse in history and second in the UK.

The UK-born mare was trained by John Gosden, too, and became an absolute legend after winning two Prix de l'Arc de Triomphe in a row. As a three-year-old filly in 2017, Enable bagged six races, including the mentioned French gem and also four other G1 races, including the Epsom Oaks. In 2018, she managed to score the Prix de l'Arc de Triomphe, which is the richest European race, for the second time and under Frankie Dettori, she then triumphed in the Breeders' Cup Turf as well. Moreover, she recorded second place in France in 2019 and reached notable prize money from additional G1 races in the UK.

4. Fantastic Light, £4,207,029

More than twenty years ago, Fantastic Light proved to be a real globetrotter as he scored big races in the UK, UAE, USA, Ireland, and Hong Kong. Thanks to participating in prestigious events globally, Fantastic Light quickly became one of the richest horses in history. Most notably, he provided his trainer Saeed bin Suroor with victories in the Hong Kong Cup Breeders' Cup Turf, while his third in the Japan Cup in 2000 was a solid one, too.

5. Lord North, £6,421,514

If anybody asks why Lord North is only fifth if his earnings are higher than Fantastic Light's, the answer is inflation. There are twenty years between the careers of these two horses as Lorn North is still in training with John & Thady Gosden, for whom the gelding has scored four G1 races. Three of them he achieved in the Dubai Sheema Classic over a mile and a furlong.