The present study is concerned with a perceptual analysis of /u/-fronting in Southern British English, Received Pronunciation and with whether there is an age-dependent difference in perceptual judgments to synthetic /i-u/ continua. A second aim was to test the hypothesis that younger listeners would be less likely to attribute a fronted /u/ perceptually to the coarticulatory fronting effects of the left context. We synthesized /i-u/ continua and embedded them in two contexts: firstly, 'yeast-used', in which the initial /j/ exerts a marked effect on /u/-fronting; and secondly 'sweep-swoop' in which the preceding /w/ is likely to induce /u/-backing. Taken together, the results of responses to these continua so far suggest that young and old listeners respond differently to a sound change in progress and also that /u/-fronting in RP may be related to a perceptual reinterpration of coarticulatory-induced /u/-fronting.