Who is the most successful British Flat trainer?

The most successful British Flat trainer of all time is Mark Johnston who, since 1988, has been based in Middleham, North Yorkshire. On August 23, 2018, Johnston saddled Poet’s Society, ridden by Frankie Dettori, to victory in the Clipper Logistics Handicap at York; in so doing, he took his career total to 4,194 winners, thereby breaking the previous record set by Richard Hannon Snr., who retired from the training ranks in November, 2013.

Johnston began his training career in 1987 and saddled over a hundred winners in a season for the first time in 1994. Remarkably, he has achieved that feat in every season since, surpassing the 200-winner mark in 2009, 2010, 2012-2015 and 2017-2019. Indeed, in 2019, Johnston sent out 249 winners, thereby setting a new record for the number of winners trained in a single season – Flat or National Hunt – in Britain.

Johnston has never won the trainers’ championship, which is decided on prize money won during the season, and it would be fair to say that, compared with the likes of John Gosden and Aidan O’Brien, truly top class horses have been few and far between. Nevertheless, at the time of writing, Johnston has 26 Group 1 victories, in Britain, Ireland, France and Germany to his name. He won the 2,000 Guineas with Mister Baileys in 1994 and the 1,000 Guineas with Attraction in 2004.