Equity's Cautious Entry into Public Law Maitland and other equity authors of his time had little or nothing to say about public law even though equitable injunctions and declarations were already being applied in that area. In 1934 Hanbury’s Essays in Equity included a chapter 'Equity in Public Law'. The author reflected upon the blurring of the public-private law divide and concluded that:
… the growing importance and unresting penetration of public law is gradually awakening our minds to the fact that it, just like private law, is composed of a medley of common law and equity, cemented by statute. It is true that there is not so much equity in public as in private law, but nevertheless a sketch of either constitutional law or criminal law that did not mention the equitable influences at work in those branches of the law would be a very imperfect and one-sided sketch.49
The intersections between equity and public law identified by Hanbury in 1934 arose in connection with:
Breaches of trust by the Crown.
The question whether a trust was a charitable trust and therefore exempt from income tax.50
The function of the Attorney-General with respect to charitable trusts.
The use of injunctive relief in public law.51
The use of injunctive relief to restrain the commission of a crime and the development of the associated doctrine of the standing requirements for a private citizen claiming relief against breach of a public right.52
Proceedings in equity against the Crown in the Courts of Chancery and Exchequer.
The development of the intersections at both the general analogical level and in the application of equitable doctrines and remedies has continued.
Principles of estoppel at common law and equity and associated preclusionary rules have been held to apply to certain categories of case although not so as to extend statutory power, contract statutory duties or fetter discretions. A statutory duty in some circumstances may equate to a fiduciary duty. Where the Crown or public bodies are assimilated to the position of private corporations or persons by the removal of Crown immunity or otherwise then equity will apply to them as it does to private corporations and persons. Statutory bodies engaged in commercial or trading activities will in their private or privatised capacity, absent any statutory immunity or modification of their liabilities, attract to their conduct the general body of the law including equity. At a more general level equity influences the development of principles of administrative law and the bases of judicial review.
Both the specific and the general interactions are reflected in the often quoted observation by Sir Anthony Mason that:
Equitable doctrines and relief have extended beyond old boundaries into new territory where no Lord Chancellor’s foot has previously left its imprint. In the field of public law, equitable relief in the form of the declaration and the injunction have played a critical part in shaping modern administrative law which, from its earliest days, has mirrored the way in which equity has regulated the exercise of fiduciary powers.53
It is helpful in this context to recall Maitland’s prophecy, cited earlier, that the day would come when lawyers will cease to inquire whether a given rule be a rule of equity or a rule of common law. It has a resonance with the further observation by Sir Anthony Mason that:
There is no reason why the courts in shaping principles, whether their origins lie in the common law or in equity, should not have regard to both common law and equitable concepts and doctrines, borrowing from either as may be appropriate, just as courts have regard to the way in which the law has been developed by statute and has developed in other jurisdictions and, for that matter, in other systems of law.54
This is not to say that the operation of equitable principles in administrative law today is in any sense comprehensive or complete. As Dal Pont and Chalmers have observed, while there is a well developed equitable jurisdiction regulating the relationships of trust between private individuals, Courts of Equity have shunned a parallel jurisdiction between government and the governed:
The relationship between government and the people has attracted the jurisprudence of equity, but in a less developed fashion. The breadth of equitable remedies are, with limited exceptions, available to plaintiffs who establish the relevant cause of action against the government. Similarly, public sector organisations and agencies are generally subject to equitable doctrines. There is no reason for equity not to apply in public law, as otherwise there would be inconsistency with the accepted social and legal policy of equality before the law, with all having access to the same rights and remedies. Equity and public law is a subject of only rudimentary perusal by commentators, and remains largely unexplored by the courts.55