Research over the last two decades has revealed a rich record of Lower Palaeolithic occupation in Britain before 450 000 years. Acheulean industries (Mode II) first appear in the later part of the early Middle Pleistocene [Marine Isotope Stage (MIS) 19-13]. This paper reviews: (i) the age of the earliest Acheulean in Britain; (ii) the climates under which the earliest Acheulean industries occur, as recorded by the palaeoecological assemblages that are found at key archaeological sites; and (iii) the spatial and temporal pattern of regional climate change, i.e. the magnitude of glacial/interglacial cycles that occurred as a backdrop to the first arrival of Mode II archaeology in Britain. This review suggests that in Britain, the earliest Acheulean populations arrived during MIS 13 and that early occupation occurred under a range of climatic/environmental settings but frequently under post-temperate late interglacial or interstadial-type cool boreal environments. Furthermore, this review shows that the pattern of climate forcing in Western Europe during MIS 13-12 was not analogous to the interglacial cycles of the past 450 000 years as latitudinal climate gradients appear to have been less pronounced. The paper concludes by discussing the significance of these observations for understanding the arrival of the earliest Acheulean in Britain.