Rod Millman praised Sergeant Cecil as a once-in-a-lifetime horse after the stayer passed away at 25.
Sergeant Cecil won 10 races and placed 14 times, rising from low-key handicaps to win the Prix du Cadran.
In 2005, he triumphed in the Northumberland Plate, Ebor, and Cesarewitch, then moved up to Lonsdale Cup, Doncaster Cup, and Yorkshire Cup wins.
Millman said, "He was fantastic, one of the toughest horses I’ve ever known."
Initially with Seamus Mullins, Sergeant Cecil joined Millman in 2002 and took time to succeed.
"He changed everyone’s lives when we had him," Millman added.
Despite his breeding, Sergeant Cecil excelled as a stayer, surprising many with his success.