Matt Campbell, 29, who was a semi-finalist in MasterChef: The Professionals in 2017, collapsed at the 22.5 mile mark.
A statement on London Marathon’s official Twitter page, said: “With deep sadness, we confirm the death of a participant in the 2018 Virgin Money London Marathon.
“Matt Campbell, aged 29, a professional chef from the Lake District, collapsed at the 22.5 mile mark and, although he received immediate medical treatment on the scene from race doctors, he died later in hospital.
“Matt was a well-known chef who featured in Masterchef: The Professionals last year, inspiring viewers with his Nutritional Gastronomy movement and forward-thinking ideas. He was running for The Brathay Trust and in memory of his father, Martin, who died in the summer of 2016.
“Matt’s family today paid tribute to their inspirational son and brother, who was a keen marathon runner and had earlier this month completed the Manchester Marathon in under 3 hours.
“Matt’s chosen charity, The Brathay Trust, inspires vulnerable young people to make positive changes in their lives.
“Everyone involved in the organisation of the London Marathon would like to express our sincere condolences to Matt’s family and friends.
“No further details will be released and the family has asked for privacy. The exact cause of death will be established by later medical examination.”
The marathon was Campbell’s second in two weeks after completing a race in Manchester.
According to his biography on his website, Campbell began his career working in Michelin-starred kitchens after finishing second on BBC Young Chef Of The Year at the age of 20 in 2009.
Speaking about running the marathon in honour of his late father Martin, he wrote on Instagram in February: “Words can’t describe how honoured and humbled I feel to be asked to run this year’s @londonmarathon on behalf of @brathaychallenges/@brathaytrust and in memory of my Father, Martin Campbell.
“It’s been almost 18 months since I lost my Dad and this has been the most challenging period of my life.
“One thing that has helped me immensely is running and he inspired me to undertake my first marathon (Brathay) in 2016.
“I would never have believed 2 years on I would have the opportunity to represent such an incredible charity at such a prestigious event. Fundraising for Brathay with the proceeds going towards their memorial appeal in my Father’s name.”