Gregor Gall examines some recent success stories of union membership growth which buck the underlying trend of decline over the past 30 years - one is organising employers through partnership deals (Usdaw), another is a focus on professionalism (NAS/UWT & NUT) and the the third is militancy (RMT). It is notable that in each case the unions have been operating in either a stable or expanding labour market:
http://www.morningstaronline.co.uk/index.php/news/content/view/full/128145