The trade union bill, which recently received its second reading, confirmed unions' worst fears of what the Conservatives would do with a majority. Strikes will require 50 per cent turnout to be legal (with those in "essential services" also requiring 80 per cent to vote in favour), employers will be permitted to hire agency staff to replace workers who walk out, and unions will be forced to give 14 days' notice of industrial action, including any proposed use of placards, loudspeakers, blogs and social media.

At today's New Statesman fringe at the Lib Dem conference (on what the EU referendum means for workers), TUC general secretary Frances O'Grady observed: "This is the last Lib Dem fringe I'll be able to address before people who exercise their democratic right to strike in this country are forced to wear armbands, have their Facebook and Twitter accounts trawled and hand over their names and telephone numbers to the police. I'm going to enjoy this while I can but, again, I would like just to put on record my thanks to the Lib Dem MPs and others who have helped us in challenging what is a deeply, deeply illiberal piece of legislation."

In response, fellow panellist Nick Clegg said he shared O'Grady's "dismay" at the trade union bill, which he denounced as "gratuitous, unjustified, disproportionate and, from my point of view, recycling lots and lots of measures that I consistently blocked within government." He added, however: "I do sometimes wish, this is going to sound terribly churlish, I do sometimes wish that your members, who worked so hard to dislodge Lib Dem ministers, realise quite how much we were doing to fend off these attacks on their rights." It will be up to Tim Farron, who delivers his first conference speech as leader on Wednesday, to persuade trade unionists to take another look at his party.

Clegg went on to warn that those unions prepared to support EU withdrawal were in danger of "unwittingly doing the job and the handiwork of the right". He added: "Let's say, let's imagine if the trade union movement were to conclude after this renegotiation - we don't like what it is, we don't like the Conservatives constantly going on about the single market but not talking about workers' rights and so on - we are going to, at bes, remain indifferent in this referendum or at worst campaign to leave. And then we leave and then what, and then what? Then we have a weaker economy with fewer jobs and with fewer rights because all the remaining rights will be scrapped in the rubble of our exit from the European Union. And with a Conservative government likely to remain in power for a jolly long time, they'll probably go even further and remove all sorts of domestic provisions as well. It would be an astonishing boomerang for the left and for the trade union movement."