John Disley, co-founder of the London Marathon and 1952 Olympic 3000m steeplechase bronze medallist, passed away in hospital early on Monday (8) at the age of 87 after a short illness.
The Welshman helped create the London Marathon – which was run for the first time in 1981 – along with founding race director Chris Brasher, and was responsible for designing the course.
Prior to that, Disley – born in north Wales in 1928 – was a distinguished athlete and represented Great Britain at several major international championships, including two Olympic Games.
In addition to his bronze medal in 1952, he also finished sixth four years later in Melbourne.
He and 1956 Olympic 3000m steeplechase champion Brasher subsequently became pioneers of orienteering in Great Britain, before creating the London Marathon following a visit to the New York Marathon in 1979.
Three-time London Marathon women's winner and IAAF ambassador Paula Radcliffe was among those that paid tribute to Disley, writing on Twitter: "Very sad to hear this - a wonderful man who had a dream that is The London Marathon. As a runner, thank you x RIP.''
Nick Bitel, chief executive of London Marathon Events, said: "John was the architect of the original London Marathon route. Every runner of the race since 1981 owes him a great debt for the vision he realised alongside Chris Brasher.
"The fact that we are celebrating our millionth finisher this year is a testament to the conviction John had that this would be an event to span generations of runners," added Bitel. "He will be greatly missed by all of us at the London Marathon."
Hugh Brasher, son of Chris and event director of London Marathon Events, said of Disley: "He inspired so many people with his love of running and the outdoors and has left a legacy that is now part of the fabric of British society."
The IAAF would also like to pass on its sincerest condolences to John Disley's family and many close friends.
London Marathon for the IAAF