SPIRITS were running high at the Trades Union Congress in Brighton. Amid stalls selling T-shirts emblazoned with pictures of Che Guevara and “I still hate Thatcher” mugs, people talked animatedly about Jeremy Corbyn, the new Labour leader. At meetings, union representatives and grass-roots activists thundered against a trade-union bill, which passed its second reading in Parliament during the conference, on September 14th. Yanis Varoufakis, the former Greek finance minister, received a standing ovation from an audience of around 600 people. On the penultimate day, Mr Corbyn himself made an appearance. “It’s not normally this interesting,” admitted one union representative. Trade unions in Britain are far less mighty than they once were. Membership has fallen from a peak of 13m in 1979 to 6m now; the number of days lost to strikes is at historic lows. Members of trade unions are older than the average worker, and the wage premium (that is, the difference in pay between unionised and non-unionised workers) has fallen from 15% in the 1990s to 5% now. Unlike American employers, who see unions as a nuisance, few British employers fear them: in the...