The law says that, where an independent trade union is recognised by the employer, the union is entitled to be given information that is relevant to the scope of its recognition and material to the issue being negotiated, and the disclosure of which is in accordance with good industrial relations. Examples may include information about a company's financial position in a pay claim or investment plans in a redundancy situation and future plans in both cases.
There is an Acas Code of Practice setting out guidelines and recommended best practice for parties engaged in collective bargaining (PDF, 475KB).
Complaints alleging failure by employers to disclose relevant information may be made to the Central Arbitration Committee (CAC), who may make a declaration and could eventually make an award of compensation against the employer. In practice, this kind of complaint is normally resolved through conciliation with the help of the CAC, without a formal hearing.