Updated 18 October 2011
Very useful Standard Note by Christopher Barclay in the Commons Library. Updated 6 October 2011.
It is on the public website at: http://www.parliament.uk/briefing-papers/SN05378.
Update 30 September 2011
The Commons Library has moved to a new system of publication for all their research briefings. This includes Research Papers and Standard Notes.
For an overview visit this page of ours: www.w4mp.org/library/guides/parliament-guides/the-library/library-briefing-papers-research-papers-and-standard-notes/