A.V. Dicey, the eminent British constitutional lawyer, famously articulated the concept of the Rule of Law in the late 19th century, which significantly influenced the development of administrative law. His three postulates – the supremacy of regular law, equality before the law, and the constitution as a consequence of judicial decisions – were foundational. However, his skepticism towards administrative law, viewing it as a continental anomaly that threatened individual liberty and the Rule of Law, marked a particular phase in its evolution. Indeed, the journey of administrative law has moved significantly beyond Dicey's narrow and somewhat hostile perspective.

Dicey's primary concern was that a separate body of administrative law, with specialized tribunals and different rules for public officials, would create a privileged class and undermine the principle of equality before the law. He believed that ordinary courts applying ordinary law were sufficient to control administrative action. This view, while influential, failed to anticipate the complexities of the modern administrative state.

How Administrative Law has Evolved Beyond Dicey:

1. Growth of the Administrative State: The 20th century witnessed an exponential growth in governmental functions, moving beyond traditional 'night-watchman' roles to extensive welfare, regulatory, and service-delivery functions. This expansion necessitated specialized administrative bodies with discretionary powers, which ordinary common law principles were ill-equipped to handle. Dicey's framework simply couldn't accommodate the sheer volume and technical nature of modern administrative actions.

2. Recognition of Discretionary Power: Modern administrative law acknowledges that public authorities require a degree of discretionary power to effectively implement policies and adapt to diverse circumstances. The focus shifted from denying such power (as Dicey implicitly wished) to controlling its exercise. Administrative law now provides mechanisms to ensure that discretion is exercised reasonably, fairly, and within legal bounds, preventing arbitrariness.

3. Development of Judicial Review Principles: While Dicey emphasized judicial control, the principles of judicial review have evolved far beyond merely ensuring legality. Concepts like proportionality, legitimate expectation, procedural fairness (natural justice), and substantive unreasonableness (Wednesbury unreasonableness) have become central. These principles allow courts to scrutinize not just whether an administrator acted within their powers, but also how they exercised those powers, ensuring good administration.

4. Emergence of Specialized Tribunals and Bodies: Contrary to Dicey's fears, specialized administrative tribunals and ombudsman institutions have become integral to modern administrative justice. These bodies offer accessible, efficient, and expert avenues for citizens to challenge administrative decisions, often providing remedies that ordinary courts cannot. They complement, rather than undermine, the role of traditional courts.

5. Focus on Public Interest and Rights: Contemporary administrative law is deeply concerned with protecting individual rights against potential administrative overreach and promoting good governance in the public interest. It seeks to balance administrative efficiency with fairness, transparency, and accountability, ensuring that the state serves its citizens effectively and justly.

In essence, Dicey's contribution was significant in establishing the Rule of Law as a cornerstone. However, his resistance to a distinct administrative law proved unsustainable. The modern administrative state, with its vast powers and complex functions, necessitated a sophisticated body of law to govern its operations, control its discretion, and protect citizens' rights. Administrative law today is a dynamic field, constantly evolving to address the challenges of governance, far surpassing the limited vision of A.V. Dicey.