A whistleblower is someone who makes a disclosure of information which they reasonably believe:

• shows one of the following relevant failures, wrongdoing or malpractice; and
• is in the public interest:
• a criminal offence has been committed, or is likely to be committed;
• a miscarriage of justice has occurred, or is likely to occur;
• a breach of any legal obligation;
• a miscarriage of justice;
• damage has been, or is likely to be, caused to the environment;
• there is, or is likely to be, danger to the health and safety of an individual; or
• deliberate concealing of information about any of the above.

Under the PIDA, a whistleblower must be a worker. The usual definition of "worker" is extended under the PIDA to include employees, trainees and consultants. Volunteers, self-employed persons or non-executive board directors are not included in the definition. However, many firms and organisations have broadened the definition – for example, the FCA offers whistleblowing protections to ex-employees and treats information obtained through a personal relationship rather than in the workplace as relevant for the purposes of a protected disclosure. However, the extended protections do not impact on the PIDA.