Results from the 2001 population census suggest that nearly 72% of people in England and Wales may be identified as Christian. This figure is substantially higher than the proportion found by the British Social Attitudes survey and other national studies. Comparing the census with sample surveys and examining different parts of the UK raises two interesting questions. Why does the census produce a higher figure than recurrent surveys for nominal Christian identification? Why, when church attendance is higher in Scotland than in England and Wales, does the census show a higher proportion of nominal identifiers in the latter? It is argued that the answer to both questions is the same: anxiety about national identity. While the census results might be taken to mean that there are more Christians than expected, such an interpretation is probably mistaken.