Employment Rights Act 1996 s.43B is entitled "Disclosures qualifying for protection"
A "qualifying disclosure" is the term used in the Whistleblowers legislation (Public Interest Disclosure Act 1998) to identify the categories of information which a worker can disclose to a suitable person without fear of reprisal (or more accurately which will give the worker rights if reprisals are taken against him for making the disclosure) provided the disclosure is made in good faith.
The Public Interest Disclosure Act 1998 inserted new sections 43A to 43L inclusive into the Employment Rights Act 1996. The definition of qualifying disclosure is therefore now in one of those sections (viz Employment Rights Act 1996 s.43B).
A "qualifying disclosure" for the purpose is defined as one which "tends to show one or more of the following:-
(a) that a criminal offence has been committed, is being committed or is likely to be committed,
(b) that a person has failed, is failing or is likely to fail to comply with any legal obligation to which he is subject,
(c) that a miscarriage of justice has occurred, is occurring or is likely to occur,
(d) that the health or safety of any individual has been, is being or is likely to be endangered,
(e) that the environment has been, is being or is likely to be damaged, or
(f) that information tending to show any matter falling within any one of the preceding paragraphs has been, is being or is likely to be deliberately concealed"
A disclosure of information is not a qualifying disclosure if the person making the disclosure commits an offence by making it (ERA 1996 s.43B(3).
A disclosure of information in respect of which a claim to legal professional privilege (or, in Scotland, to confidentiality as between client and professional legal adviser) could be maintained in legal proceedings is not a qualifying disclosure if it is made by a person to whom the information had been disclosed in the course of obtaining legal advice (ERA 1996 s.43B(4).
Provided the person making the disclosure reasonably and genuinely believed that the matters which form the subject of his disclosure are within the list above then it is irrelevant that in fact they were not. Thus for example where a (possible) criminal offence is alleged it would be unreasonable to expect employees on the factory floor or in shops and offices to have a detailed knowledge of the criminal law sufficient to enable them to determine whether or not particular facts which they reasonably believe to be true are capable of constituting a particular criminal offence - and therefore disclosure of those facts can be a qualifying disclosure even if it turns out that they did not constitute a criminal offence (see Babula v Waltham Forest College CA 2007 on 7th March 2007, overruling Kraus v Penna PLC and anor, EAT 2003 reported at  IRLR 260).
Employment Rights Act 1996 s.43B (inserted by Public Interest Disclosure Act 1998 s.1).