What to Know
Matt Campbell collapsed after 22.5 miles and died at the hospital.
He appeared last year on the BBC's "Masterchef: The Professionals."
Temperatures reached 73.8 degrees near the end of the 26.2-mile course.
A 29-year-old man died after collapsing near the end of Sunday's London Marathon in the hottest conditions ever seen for the event, race organizers said.
Matt Campbell, a chef from northwest England who was a contestant on a reality TV cooking show last year, collapsed after 22.5 miles (36.2 kilometers).
Organizers said "although he received immediate medical treatment on the scene from race doctors, he died later in hospital."
Campbell last year appeared on the BBC's "Masterchef: The Professionals."
A medical examination is still required to discover the cause of death, organizers said.
The Met Office said temperatures reached 73.8 degrees (23.2 Celsius) near the end of the 26.2-mile (42.2-kilometer) course.