The Trade Union and Labour Relations (Consolidation) Act 1992 (TULRCA) imposes duties on employers who are proposing to dismiss at least 20 employees as redundant at one establishment within 90 days or less.  One such duty is to notify the Secretary of State at least 30 days before the first of those dismissals

The Collective Redundancies Directive (98/59/EC) (the Directive) sets out consultation requirements for employers where a set number of redundancies are contemplated within a specified time frame, being either 30 or 90 days depending on the member state concerned.

In the UK, the Directive is implemented through the Trade Union and Labour Relations (Consolidation) Act 1992