Sir Bradley Wiggins has broken the iconic hour record by completing a distance of 54.526km (33.88 miles).
The 35-year-old smashed the record previously held by fellow Briton Alex Dowsett of 52.937km (32.89 miles), which was set in May.
Roared on by a capacity crowd at Lee Valley VeloPark in London, Wiggins became the sixth rider to claim a Tour de France title and the hour record.
"I'm just glad it's done. It was torturous," he said.
"That's the closest I have ever come to what it's like to a have a baby," Wiggins, who becomes the fifth person in the past nine months to break the record, joked.
The multiple Olympic and world champion on track and road surpassed Dowsett's 212 laps, set in Manchester, with 1min 42secs to spare and eventually completed 219 laps.
But the 2012 Tour de France winner fell short of the target he had set himself of 55.250km, or 221 laps.
Six riders have managed to claim the Tour De France title and break the UCI hour record
They are: Lucien Petit-Breton (France), Fausto Coppi (Italy), Jacques Anquetil (France), Eddy Merckx (Belgium) and Miguel Indurain (Spain) and Bradley Wiggins (Great Britain)
"You're constantly looking at the clock counting down. When you're out there, you never think it's coming to an end," he added.
Former British cycling performance director Dave Brailsford said it was "an honour" to witness the occasion.
"Bradley rode well on what was a heavy and hard day," he said.
"I'm so pleased for him, it's his day and he is such a magnificent athlete."