Whitehead is a natural marathon runner but turned to sprinting because there was no marathon for him to compete in at the London 2012 Paralympics. He not only stormed home to 200m gold but also to a world record.
This charity challenge is also a million pound fundraising quest as he hopes to raise at least that amount - through donations and sponsorship of people who want to run alongside him - for the charities Sarcoma UK and Scope.
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The man, in his thirties, was found with stab injuries on the upper deck of a bus in Handsworth, Birmingham, on Monday night.
Thousands of passengers now face delays, with Southeastern trains warning "all services" would be affected.
Paramedics attended a scene in Willesden, north-west London, on Monday afternoon where they found the teenager with stab wounds.