The principal of Havering Colleges ran 26.2 miles in memory of a former student who was murdered in Harold Hill last year.
Paul Wakeling completed the Lenham Cross Winter Marathon in Kent on Sunday, February 23 in memory of Sixth Form student Jodie Chesney who was fatally stabbed in Harold Hill on March 1, 2019.
The tough course involved running up and down hills and forest trails in the wind and rain on a route with 4,300ft of elevation.
Peter Chesney started the Jodie Chesney Foundation in his daughter's name.
The charity aims to make a difference to the culture of knife crime in this country and Mr Wakeling ran the marathon to raise money for the cause.
Mr Wakeling said: "Jodie was a kind and giving person and is greatly missed."
Donations can be made via a collection in admissions at the college's Ardleigh Green campus in Ardleigh Green Road or in the finance office at the Sixth Form in Wingletye Lane, Hornchurch.
Visit jodiechesneyfoundation.org.
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