Hollie Doyle has paid tribute to Glen Shiel, saying the horse holds a "very close place in her heart" after providing her with a breakthrough Group One success.
The duo combined to win the 2020 Champions Sprint on Ascot's Champions Day, with the victory proving to be a seminal moment in Doyle's career.
The eight-year-old came close to repeating his success 12 months later, but had to settle for second after finishing just one length behind Creative Force. The Archie Watson trained horse also came second in the Diamon Jubilee at the Royal meeting.
Glen Shiel has been winless in three starts this season and following a setback in training, a decision was made to call time on his career.
"He's a star and he is a horse I'll also hold very close to my heart as he gave me my first Group One," said Doyle.
"He owes nobody nothing and I'm just glad he's going to have a happy retirement.
"He's a horse who has performed consistently at the top level for the last two years.
"It was crazy how he went from being a good handicapper over a mile to being a Group One sprinter. They don't usually get quicker with age, but he did his career the opposite way around.
"He loved Ascot, he tried so hard for you and that Group One, he only won because he has the heart of a lion.
"There's a few pictures of him at home, anyway!"
The horse also meant a lot to Watson as he was the trainer's first Group One winner.
He said: "Glen Shiel has meant the world to everyone at Saxon Gate. He gave us our first Group One win at Ascot in 2020 and has been so tough and consistent in sprints at the highest level.
"He is the kindest horse and can now look forward to the long and happy retirement he deserves."
Glen Shiel was purchased by Hambleton Racing for just £45,000 out of Andre Fabre's yard back in 2019.
Looking back at his career, Hambleton Racing's Simon Turner added: "Glen Shiel is an unbelievably special horse.
"He was the fiercest of competitors on the track and provided his owners with some very special moments.
"We're incredibly proud of what he achieved and equally delighted he'll now be able to enjoy his retirement."
