The athlete’s father Robin will run in his place in the Brighton Marathon raising funds for Mind.
A former Great Britain athlete has died at the age of 28, his running club has said.
Robbie Fitzgibbon, a middle distance runner, represented his country at several international events.
His club, Brighton Phoenix, described him as “one of our most cherished athletes”.
A statement said he was “a friend to many, and a source of motivation for all who had the privilege of knowing him”.
It added: “Robbie was the epitome of a runner’s runner, embodying everything we value at Phoenix.”
Robbie Fitzgibbon joined Brighton Phoenix as a junior, and through “dedication, relentless hard work, and determination”, he became a GB senior international-level athlete, the club said.
In 2019 he competed in the senior indoor European Championships, reaching the final, and went on to compete in several Diamond League races.
His coach and mentor, Joel Kidger, said: “Robbie was talented but, even more so, a hard worker.
“He was gritty, determined, and usually got to where he wanted.”
Charlie Grice, his training partner, paid tribute, saying: “You were a true fighter who always gave your best.”
In recent years, Fitzgibbon took a step back from track running, moving from middle-distance to long distance races.
He had been preparing to run the 2025 Brighton Marathon in aid of the charity Mind.
His father Robin will now run in his place, the club has announced.
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