This contribution raises a double question about the Latin that was written by literate Celts in Britain in the early Middle Ages: to what extent does their output correspond to the Latin of their monastic contemporaries in Ireland? And is it appropriate to call it Cambro-Romance? The second issue turns upon the extent to which, following the demise of Roman rule in Britain, Latin may have continued as a language of active communication there. This is a longstanding question but, in presenting a systematic analysis of those entries so far published in the Dictionary of Medieval Latin from Celtic Sources that codify the vocabulary of British-Latin authors, the paper is able to arrive at a bettersubstantiated answer than has been possible hitherto: this suggests that the language in fact enjoyed a surprisingly deep and tenacious hold on early medieval Celtic Britain, enduring for many centuries. Turning then to the first issue, the contribution compares this scenario with the situation in Ireland. The contrast is found to be striking, and the implications are explored.