Three-time Coronation Cup winner St Nicholas has lost his battle with serious illness and been put down at seven years old.
The Aidan O'Brien-trained horse won six Group One races but suffered a leg fracture last summer and then came down with the life-threatening laminitis disease.
His owners Coolmore Stud said in a statement today that St Nicholas Abbey had been recovering well but suffered a colic during surgery that meant he had to be put down on "humane grounds".
"Surgery revealed a severe strangulating colon torsion that was unviable and he had to be euthanised on humane grounds," read the statement.
"This is extremely unfortunate as St Nicholas Abbey had been in terrific form, the laminitis was resolving very well and the fracture had healed better than expected."
St Nicholas Abbey won the Coronation Cup at Epsom three years in a row from 2011 to 2013.
