Britain had a very warm climate in the Palaeogene but it gradually cooled as Britain drifted northwards. By the Quaternary, glaciers covered the middle and north of Britain, shaping the landscape we see today. The first people occupied Britain during the Quaternary.
*Based on The Geologic Time Scale 2012 by F M Gradstein, J G Ogg, M Schmitz and G Ogg (2012), with additions.