4 trade union law essentials: Explained

Trade union law is becoming more relevant for employers across every sector — the Employment Rights Act 2025 increases the likelihood of union engagement, making a review of the fundamentals essential.

Most HR professionals in non-unionised organisations know just enough about trade union law to know they have gaps. As the Employment Rights Act 2025 increases the likelihood of union engagement across more workplaces (with workplace access and a statement of the right to join due to come in from October), those gaps carry increasing risk.

1. Trade union recognition: how it works

Recognition is the mechanism by which a union acquires formal rights in a workplace. Most recognition is voluntary, but there is a statutory route. Under Schedule A1 of the Trade Union and Labour Relations (Consolidation) Act 1992 (TULRCA), a union can apply to the Central Arbitration Committee (CAC) for compulsory recognition where it has 10% membership among the group of workers it wants to represent. That threshold is lower than many employers realise and, under ERA 2025, the government has reserved the right to reduce it further – perhaps as low as 2%.

2. Collective bargaining and collective agreements: what employers need to know

Once recognised, a union has the right to negotiate on pay, hours, and holidays as a minimum. Those negotiations – collective bargaining – produce collective agreements. The agreements themselves are generally not legally enforceable between employer and union, but where their terms are written into individual employees’ contracts, they become binding. The distinction matters when you are handling redundancy, restructuring, or contract variation.

3. Trade union representatives: rights and protections

Representatives are employees elected to act on behalf of union members. They are entitled to paid time off for trade union duties and they have significant legal protection. Dismissal connected to union membership or activities is automatically unfair – no qualifying period required.  Any HR decision touching a representative – disciplinary action, or redundancy selection – requires particular care.

4. Industrial action and strikes: the legal framework

Both are tightly regulated. Lawful action requires a properly conducted ballot and formal notice to the employer. Where those conditions are met, employees gain some protection from dismissal. Where they are not, the legal position shifts considerably. Taking early legal advice at the first sign of collective action is essential.

Tips for employers

The worst time to think about your union relations strategy is when a recognition request has already landed. By that point, your options are narrower and your decisions are under pressure.

The better approach is to treat union engagement as part of your broader employee relations planning – not a contingency for if things escalate, but a standing consideration.

In practical terms, that means:

• Keep an eye on the external environment
  Are unions active in your sector? Are they publicly targeting employers of your size or type? Trade unions are increasingly strategic about where they focus their organising efforts, and forewarned is forearmed.

• Pay attention to internal signals
  Rising grievances, declining engagement scores, or pockets of employee dissatisfaction are the conditions in which union organising takes hold. Address the underlying issues rather than waiting to see whether a union gets there first.

• Have a plan before you need one
  Decide now how your organisation would respond to a recognition request, an access request, or an approach from a union official. Who owns it? What are your principles? A framework prepared in advance is considerably more useful than one drafted reactively under time pressure.

Further reading

• S 59 Employment Rights Act 2025 – UK Government
• Key Trade Union Changes – Hunter Law
• Employment Rights Act 2025: Imminent employment law changes – Hunter Law

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