https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/32191/11-p77-trade-union-membership-2010.pdf

Numbers are far lower than in the 1960s and 1970s but they still represent nearly 29% of all workers.

By contrast the major political parties have withered to virtually nothing. For example the Conservative Party which once numbered nearly 3 million now has only about 150,000 members. The Labour party has shrunk from 1 million down to 193,000 members. The Liberal Democrats have about 49,000 members.

http://www.parliament.uk/briefing-papers/SN05125

Twice as many people belong to trade unions as buy Rupert Murdochs papers the Sun and the Times, and Unite alone has far more members than the Daily Telegraph has readers

http://en.wikipedia.org/wiki/List_of_newspapers_in_the_United_Kingdom_by_circulation
http://en.wikipedia.org/wiki/Unite_the_Union

The truth is that the Trade Unions are not a dead weight holding back the Labour Party. It is the other way round.

BTW as a life long Union activist I am not saying everything in the Union movement is roses at present Too many union bosses are remote from their members, turnouts in union elections are appallingly low and some TU officials spend far too much time on advancing personal political agendas than in fighting to defend their members jobs, terms and conditions. That said they are still far more representative of ordinary working people than any other set of institutions in the UK.

The irony of party politicians and media hacks whose own houses are tumbling down around their ears calling Unions outdated should not be lost on people