Today marks the House of Lords coming to grips with the government’s Trade Union Bill. The Bill has been widely condemned and seems to enjoy little support beyond Westminster and Whitehall.

Led by the TUC, unions have responded with a vigorous campaign against the Bill and won some notable concessions in the House of Commons. Police powers have been shaved, and the government has yielded to pressure, by withholding proposals to require unions to give notice to a State official of protest plans and anticipated social media use during the course of a dispute.

But in truth these are minor victories. This still leaves a monster that is in clear breach of Britain’s international legal obligations, by undermining freedom of association, the right to bargain collectively, and the right to strike.

Further concessions may nevertheless be secured in the House of Lords, where the focus will be the right of employers and unions to agree to ‘check off’ arrangements, whereby the employer deducts trade union dues from workers’ wages (with the consent of the workers in question), before passing the money over to the union. This is a convenient way for workers to pay their subs, but it is to be banned, without any adequate explanation.

Focus will also be on the new rules on the trade union political levy, the default position being changed in what is a clear and cynical attempt to reduce trade union funding of the Labour Party. This of course is not the only government attack on its opponents, the Bill coming soon after the Gagging Act 2014 cut the ability of unions to campaign in elections, and at the same time as Osborne’s decision to slash ‘Short’ money to parties in Parliament.

Finally, there is likely also to be renewed concern about the swingeing restrictions on the right to strike. Although there are many new restraints on strikes in the Bill, the headline issue is the requirement of a minimum 50 per cent ballot turnout to legalise all disputes, and a minimum 40 per cent support threshold in disputes in important public services. A core issue here is the continuing ban on the right of trade unions to hold secret ballots at the workplace.

The House of Lords has already shown an independent streak, notably in its rejection of Osborne’s tax credit cuts. The question now is whether the Lords has been emboldened or chastened by that experience.

The nature of the government’s ‘mandate’ for far-reaching change of the kind to be seen in the Trade Union Bill is highly contestable. Supported by only a third of the votes of those who voted and only a quarter of the electorate, this looks more like a coup d’etat by ballot box than an expression of democratic politics.

The first injunction under the Bill will be challenged on human rights grounds (whatever happens to the Human Rights Act), in what will be the start of a long guerrilla campaign against the Bill in the courts.

But litigation takes time and has unpredictable outcomes. What is predictable, however, is that trade unions will adapt to the new legal regime in ways that will make them harder to control. Len McCluskey of Unite has already warned an audience of industrial lawyers that if legal restrictions on the right to strike are pushed too far then workers will take the law into their own hands. Indeed, Unite has removed from its rulebook the constraint that it will only fulfil its objectives ‘so far as may be lawful’.

Denied the right to strike, workers may find other ways to express their grievances. So if the past is to be any guide to the future, we may well find that trade union activists develop a different relationship with their unions. As a result, we may see more informal, disorganised, spontaneous ‘wildcat’ action of the kind that has been associated with recent disputes in the construction industry. This will be much harder to contain.