A collective agreement requiring members of a particular group of employees to be or become members of a specified trade union. A pre-entry agreement is one that prohibits an employer from engaging a relevant employee unless he is already a member of the union concerned. A post-entry agreement requires employees to join the specified union within a certain time after the employment commences.
Under the Trade Union and Labour Relations (Consolidation) Act 1992, all employees are free to join a trade union or not, as they wish. If an employer takes action, short of dismissal, against an employee to enforce membership of a union, the employee can complain to an employment tribunal, which can order the employer to pay him compensation. Dismissal for failure to belong to a trade union is automatically unfair (see inadmissible reason). In this case there are special minimum rates of compensation payable. If, as a result of trade union pressure, an employer dismisses an employee for failing to belong to a union, the employer can join the union as a party to the dismissal proceedings and pass the liability to pay compensation on to the union.
A union that attempts to enforce a closed shop by industrial action loses the immunity from legal action that it would otherwise have if the action was in furtherance of a trade dispute.
The effect of these provisions is that, while closed-shop agreements are not in themselves illegal, they are unenforceable by either employers or unions.