The row over government minister Peter Hain's deputy leadership election expenses, apparently siphoned through an alleged think-tank, has raised questions about what these beasts are, exactly.
The BBC's website has offered an analysis here. http://news.bbc.co.uk/1/hi/magazine/7189094.stm [1]
Inter alia it comments on Ekklesia, as follows: '[T]here are the single-name classical sounding groups like Demos, centre-left, favours "everyday democracy"; Politeia, centre-right, "forum for social and economic thinking"; and Ekklesia, "promotes transformative theological ideas in public life".'
Actually, Ekklesia's name is a biblical term. FAQ: http://www.ekklesia.co.uk/about/faqs/10 [2]
See also: "learning to think without tanks" http://www.ekklesia.co.uk/node/5942 [3]