Employment Tribunals Act 1996 s.18 is entitled "Conciliation".
This privilege is based on public interest considerations, ie the desirability of bringing parties to agreed "out of court" settlements (see Grazebrook (M&W) Ltd v Wallens NIRC 1973 ICR 256, NIRC).
Normal communications are, however, not protected by legal privilege so, for example, communications between an employer and a firm of personnel consultants in relation to the disciplining and dismissal of an employee are not protected, are admissible in evidence and can be the subject of cross-examination. Legal professional privilege is strictly confined to legal advisers such as solicitors and counsel who are professionally qualified members of professional bodies, are subject to the rules and etiquette of their professions and owe a duty to the court and in the case of solicitors are technically officers of the court ( New Victoria Hospital v Ryan 1993 ICR 201, EAT).
See also notes at ACAS/COT3 procedure and conciliation