The key development is the emergence of Grooved Ware - a phenomenon that occurred in Orkney, with the Pool ceramic sequence offering the key to its origins (MacSween 1992, 1999, 2007). As indicated above, the precise date of its emergence remains a little obscure, but Schulting et al. (2010) have concluded that it was very probably in use by 3200 BC. Its emergence seems to be related to the social dynamics of Late Neolithic communities in Orkney, where a system of competitive conspicuous consumption operated. The key features of Orcadian Grooved Ware have been defined by MacSween and Cowie (1999) and Sheridan (1999), and the very close similarities between some Grooved Ware from Orkney and far-flung Grooved Ware from southern England have long been recognised - indeed, in the original use of the term 'Rinyo-Clacton' ware.
That Grooved Ware in different parts of Britain and Ireland followed different (and sometimes convergent) trajectories is clear, but many more high-quality dates are required in order to define the nature of these trajectories in detail.