The overall lack of a conclusive definition of the ‘public interest’ has led to mixed approaches in the way in which those who leak confidential information are handled, as well as the legal protection that is afforded to such people, should they decide to leak information. Although some case law has provided an insight into the circumstances whereby a public interest test is likely to be satisfied, the law is still wholly inconclusive as to what the ‘public interest’ really is. Thus, allowing for great uncertainty within the law and creating problems in regard to whistleblower protection.
Early case law has suggested that the ‘public interest’ would suffice as an exception to the non-disclosure of confidential information, where there is ‘any misconduct of such a nature that it ought in the public interest to be disclosed’  or with ‘just cause or excuse’ . This early common law, therefore, set the boundary in breach of contract cases, whereby public interest was eligible as a defence to disclosure of confidential information, even in situations where the motive of the whistleblower was in dispute . However, a public interest defence in this respect was consequently criticised as being ‘an invitation to judicial idiosyncrasy’ rather than a genuine rule of law  and although boundaries were set, no legitimate definition arose.
Despite the fact that the Public Interest Disclosure Act (PIDA) was introduced in 1998, there was still an absence of a ‘public interest’ test in the statute. The Enterprise and Regulatory Reform Act (ERRA) 2013 amended PIDA in an attempt to resolve this ‘loophole’  These additional provisions have been argued to increase ‘the confidence of whistleblowers in the protection afforded by PIDA’, which has, in turn, arguably increased the certainty of protection under the legislation. The ERRA appended that in order to determine whether a disclosure by a worker would suffice as a qualifying disclosure, it would have to be proven that the whistleblower reasonably believed disclosing such information was ‘in the public interest’. However, although ‘public interest’ was specifically mentioned in the statute, still no definition was stated. Thus, the issues surrounding the lack of a conclusive definition remained.
Although in certain areas of law, what would suffice as meeting the interests of the public is perhaps easier to determine, such as failings in education and prison services, other types of disclosures are not as transparent. The recent case of Chesterton v Nurmohamed affirmed that workers’ ‘reasonable belief’ that their disclosure was made in the public interest contained both an objective and a subjective element. It was concluded in this case that even in instances of predominately private interests if there are nevertheless features of the case which are of public concern, it can be established that the unauthorised disclosure was in fact made in the public interest. As a result, the already broad interpretation of ‘public interest’ was extended even further.
In addition, the appeal judges cited the original tribunal, agreeing that they were ‘not aware of any case law in existence as yet, which identifies the proper meaning of public interest’.Therefore, highlighting the inconsistent approach of the courts and making it extremely difficult for whistleblowers to have any real sense of certainty as to the level of protection, if any, that they ought to be afforded.
Nevertheless, this broad interpretation of the ‘public interest’ can also be beneficial in some instances. It provides judges with ‘a sufficient degree of flexibility’ to be able to determine each case on an individual basis. For example, the case of B & C v A saw the Court of Appeal conclude that it would be impossible to provide a definition of the ‘public interest’, as the circumstances of each case can vary greatly and therefore, the decision that applies in one case may not be the correct decision in another.
However, although this broad use of ‘public interest’ does enable judges to apply this term more freely in factual situations, it is also recognised that this is a ‘major disadvantage’ to potential litigants, who cannot predict with any certainty how this will be applied.
It is therefore concluded that although both PIDA and common law do provide useful guidelines on disclosures which would be made in the public interest, these guidelines are ‘riddled with uncertainty’ as much is left to judicial discretion. This uncertainty ‘leaves a gap in the protection afforded to whistleblowers, creating a risk [which] workers would not be willing to take’. As a result, if whistleblowers are uncertain whether they will receive adequate protection, they are likely to opt for the safest option – to stay silent. This is an unsatisfactory consequence of the law and therefore a uniform definition of the ‘public interest’ should be established. This would ensure certainty within the law, providing whistleblowers with an adequate level of protection and encourage disclosures which are genuinely in the ‘public interest.’
Initial Services v Putterill 1 QB 396
Laboratories Ltd. v Evans QB 526
see Re a Company’s Application IRLR 477
SK & F v Department of Community Service FSR 617 (Gummow J)
Department for Business Innovation and Skills, ‘Enterprise and Regulatory Reform Act 2013: Policy Paper’ (Gov.uk, June 2013) <https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/209896/bis-13-905-enterprise-and-regulatory-reform-act-2013-policy.pdf> accessed 26 February 2018
Kelly Bouloy, ‘The Public Interest Disclosure Act 1998: Nothing more than a “Cardboard Shield”’  1(1) Manchester Student Law Review 1
in addition to meeting one of six categories outlined in PIDA
see Jeanette Ashton, ‘When Is Whistleblowing in the Public Interest? Chesterton Global Ltd & Another v Nurmohamed Leaves This Question Open’  44(3) Industrial Law Journal 450
Chesterton Global Limited & Anor v Nurmohamed EWCA Civ 979
Confirming Babula v Waltham Forest College EWCA Civ 174
(n 6) para 14
Ashley Savage, ‘The Public Interest in Public Interest Disclosure’ (HRreview, 4 September 2012) <http://www.hrreview.co.uk/analysis/analysis-employment-law/ashley-savage-the-public-interest-in-public-interest-disclosure/38668> accessed 26 February 2018
 EWCA Civ 337
David Lewis, ‘Is a Public Interest Test for Workplace Whistleblowing in Society’s Interest?’  57(2) International Journal of Law and Management 141