Government actually collects quite a lot of data pertaining to religion in Britain, but you would not think so if your only evidence was the Annual Abstract of Statistics.
The latest (and last) print edition (No. 146 for 2010) was published by Palgrave Macmillan on 15 July, edited by Ian Macrory.
So far as can be seen, it contains not a shred of religious data (unless you count the appearance of The Passion of Christ in the list of box office top 20 films released in the UK and Ireland in 2004-07).
By all means, check this assertion out for yourself at the following URL (where the book is freely available online):
A search under ‘religion’ on http://www.data.gov.uk likewise surfaces relatively little for Britain at the moment, other than the 2001 census (although the commissioned tables, of particular interest for religion, apparently still have to be requested); the Citizenship Survey; and the religious profession of members of the armed forces.
In particular, basic tables by religion from the Annual Population Survey/Labour Force Survey do not seem to be readily accessible. While it is fine (and commendable) that the datasets are available for secondary analysis via the Economic and Social Data Service, surely we need some aggregated statistics in an online published format?
Given that the Government is openly discussing the discontinuation of a decennial population census after 2011 (and, with it, implicitly the loss of the religious question), is it possible for Government statisticians to consider repurposing and making available online a wider selection of such religion data as they have from other sources?