The Cenozoic sedimentary basins on the Atlantic margin of northwest Britain contain a remarkable record of tectonically influenced post-breakup sedimentation. We have mapped the distribution and quantified the solid grain volume of four unconformity-bound successions in the region, the Eocene (∼6–8 × 104 km3), Oligocene (∼2 × 104 km3), Miocene−lower Pliocene (∼4–5 × 104 km3) and lower Pliocene–Holocene (∼4–5 × 104 km3), complementing previous work on the Paleocene succession. Of the total Cenozoic sediment volume on the Atlantic margin of northwest Britain, ∼80% was deposited in Eocene and later time. The relative volumes of the Cenozoic succession do not support previous claims that the Paleocene was the main period of Cenozoic uplift and erosion of sediment source areas. Rather, the Cenozoic sedimentary basins on the Atlantic margin of northwest Britain record the detritus of four major episodes of Cenozoic uplift of the British Isles (Paleocene, Eocene–Oligocene, Miocene, and Pliocene–Pleistocene).