A 93-year-old hopes to beat the record for the oldest man ever to run a marathon - but he will not do it this year.
Fauja Singh ran his first marathon five years ago
Fauja Singh, from Redbridge, Essex, is five years too young for that feat, but will still be the oldest person at Sunday's London Marathon.
He says he runs to increase the profile of Sikhism but also raises money for charities.
Dimitrion Yordandis, who ran the Athens race aged 98, holds the current record.
After running the New York marathon after the 11 September attacks, Mr Singh was awarded the Ellis Island medal - given to ethnic minorities for their contribution to the USA.
He said: "Not only is running the marathon a personal achievement, it also gives everybody recognition of the Sikh community, showing they are part of the wider world."
He ran his first marathon five years ago, and on the challenge this year he said: "Every year it gets harder.
"But I am more mentally prepared because I know what I am up against."
Fauja Singh runs about 10 miles a day
He hopes to beat last year's Toronto marathon time of 5 hours 40 minutes.
He started running in his Punjab village but stopped after the "pain of the partition of India" in 1947.
He moved to the England 11 years ago to live with his son after the death of his wife and started to run again to help him "concentrate his mind".
His training consists of running about 10 miles a day and he also meditates everyday for about three hours.
And sportswear company Adidas has signed him for its 'Nothing Is Impossible' ad campaign.
Jenny Wood-Allen is the oldest woman to finish the London marathon, aged 90, in 2002.