A number of recent studies of the UK coastal environment have assessed the C-14 marine radiocarbon reservoir effect (MRE) via quantification of Delta R values for several periods throughout the Holocene using marine mollusc shells. However, none have employed fish bone as the marine sample, and the importance of being able to use this material as a reliable dating tool is evident when considering the boom in the British fish trade during the first millennium Delta D, the so-called 'fish event horizon', and the corresponding volume of fish remains that appear in the archaeological record from this time. This study compares Delta R values derived using the multiple paired sample approach employing burnt cereal grain (Hordeum sp.) as the terrestrial sample and either fish bone [North Sea cod (Gad us morhua)] or marine shell [limpet (Patella vulgata)] as the marine sample. The results show a general trend of increasing Delta R for the fish bone compared to shell, however, the differences are not statistically significant when the standard error for predicted values is used as the measure of variability in the Delta R values. (C) 2010 Elsevier Ltd. All rights reserved.