John Bishop had to battle a new ailment as he enters the last leg of his "week of hell" - in the form of painful shin splints.
Within moments of setting off on his final marathon distance, the comic had to stop due to the condition affecting the tendons in his legs.
But the 45-year-old star - who has cycled, rowed and run from Paris - pressed on in a bid to reach his intended destination London this afternoon (Friday).
He has battled exhaustion, severe aches and pains, sickness and sleep deprivation since setting off on Monday. Bishop has endured a 185-mile cycle, rowed across the English Channel and completed two marathon distances to reach today's starting point, Gravesend in Kent.
The Liverpudlian comedian said: "It feels like a month ago that I was on the boat. It's just a blur and it'll take a bit of time for it all to sink in."
On Wednesday night he struggled to hold down food but he told Radio 1's Chris Moyles today that he was able to eat again. "I'm now eating for Africa," joked the comic, who is raising cash to pay for vaccinations for African children through the BT Sport Relief Challenge.
Bishop - who has seen his route lined by well-wishers - said he was largely unaware of the "jamboree" going on around his challenge.
"I'm basically just doing my stuff and going to bed," he said.
His physio team has had to administer regular massages and ice baths to keep him going and his legs have been strapped up to ease terrible pains in his achilles.