Lloyd Cowan, who coached Christine Ohuruogu to the 400m Olympic title in 2008, has died at the age of 58, British Athletics has confirmed.
Cowan competed in the Commonwealth Games as a hurdler and went on to have significant success as coach to a number of high-profile athletes.
British Athletics said: "We are deeply saddened by the passing of Lloyd Cowan MBE. Our thoughts are with his family and friends at this time."
Under Cowan's tutelage, Ohuruogu won two 400m world titles as well as the Olympic crown in Beijing.
He also coached Andy Turner to Commonwealth and European 110m hurdles titles in 2010 before world championship bronze in 2011.
Turner tweeted that he was "absolutely heartbroken" to learn of Cowan's passing, adding: "I owe him everything."
Linford Christie also tweeted his condolences, adding: "The space you left cannot be filled".
Cowan's son Dwayne is an international athlete who won a bronze medal as part of Great Britain's 4x400m relay team at the 2017 World Championships in London.