He is one half of the duo known as the Wide Boyz, along with his climbing partner Tom Randall.
In 2011, Whittaker and Randall made a visit to the United States, where he was the first to flash Belly Full of Bad Berries (5.13b), a highly regarded off-width in Indian Creek.
[1] Continuing the trip, Whittaker and Randall made the first ascent of the Century Crack (5.14b), the world's hardest off-width climb.
[6] In 2021, Whittaker and Randall free-climbed the Great Rift (5.13), a 2,500-foot roof crack on the underside of a highway overpass in Devon, England.
[7] Their ascent was documented in the short film Bridge Boys, which was featured in Reel Rock 16.