It is the slippery assemblages and the social traditions they represent, that we are trying to precipitate from the mass of beaker data'. Clarke 1970, 33 The pottery we collectively call 'Beakers' is united by the thread of a potting and style tradition, trapped up in that tradition are also expressions concerning what such a pot is for and who it may represent. Both style and those embedded meanings mutate through the long currency of British Beakers. Indeed, the newly emerging chronology for Beaker grave groups suggests that there was one critical point of rapid mutation in both pot form and associated artefacts. This phase is referred to as a fission horizon, c. 2250-2150 cal BC, and it underlines the difficulties that past schemes of steady evolution have run into. In reviewing the continental background for Beaker-carrying cultures, a corridor of Bell Beaker/Corded Ware fusion is perceived along the southern flanks of the Channel. This created a modified spectrum of Beaker culture which stands at the head of the insular phenomenon. The long ensuing currency of Beaker pottery and Beaker graves in Britain does not hold up as a unified, steadily evolving entity. Instead, three 'phases of meaning' can be suggested: 1) Beaker as circumscribed, exclusive culture; 2) Beaker as instituted culture; 3) Beaker as past reference. The fission horizon initiates phase 2.