The latest British Social Attitudes survey is available from NatCen Social Research. The methodology for the survey is as follows:
The people selected to participate in the survey are chosen using a technique called random probability sampling. This technique ensures that everyone has a fair chance of being picked to take part and the results are representative of the British population. Once selected, participants are interviewed in their homes by one of NatCen’s interviewers.
Findings from the survey indicate some interesting things, but you have to go to the technical details sections of the report to find the good stuff.
48.9% percent of respondents identify as “no religion,” which is up from 43 per cent in 2004. You can read more about the survey at the National Secular Society, which also points out a “ten-fold increase in those identifying with Islam in the past 32 years.” I wasn’t able to find the Islam data and got tired of looking, but I’m going to take their word for it.