This chapter analyses the first prime minister, Robert Walpole, against Boris Johnson – the prime minister at the time of the office’s 300th anniversary. The two PMs bookend 300 momentous years of history, but what has changed about the office of prime minister? Comparing personal and political, the chapter examines the machinery of government, from patronage in Parliament to departmental power as well as the core driver for the role of prime minister. While the country and office have changed, some core functions and political realities remain the same in the British system.

In this chapter, we explore how the transfer of power between the monarch and the prime minister occurred, when it happened, how the monarchy survived, the importance it still has in Britain, and how far the prime minister has effectively become the head of state as well as head of executive. The monarchy continued to exercise real authority for the first 200 years of the prime minister’s existence and beyond, up to today. The rebalancing of power was painful, faltering, and contested. Scratch below the surface, and the relationship between head of state and head of government has been far from settled. The continued existence of an independent prime minister was not a given in the eighteenth century. The continued existence of the monarchy until today has not been a given either. It had been abolished in Britain in 1649, as it was in France in 1792 (and 1848 and 1870), Germany in 1918, and Italy in 1946. It would have been vulnerable in Britain had there been military defeat or successful revolution: its continuation into the future is not assured. Monarchies are going out of fashion. Britain’s has held strong.

The prime ministers all play chess on a multi-dimensional board, prey to challenges that vary in type and intensity over time, some of which are new and growing, and others constant. The most skilful negotiate their way through these constraints, turning them to their advantage, and refuse to be defined by adversities. The least able are swallowed up by them. We first consider institutional restraints, the checks and balances they face, some dating back to 1721, before considering variable constraints, which have made and destroyed premierships, and have rendered even the best-qualified incumbent a cornered animal.

Not all prime ministers are equal. Not remotely – which is why books taking one prime minister after the other can only ever tell a partial story. In this chapter, we consider the other seven (after Walpole and Pitt the Younger) who defined the office as ‘agenda changers’. They are the creators of the (still evolving) office of prime minister. All nine – two in the eighteenth century, three in the nineteenth, and four in the twentieth – carved out what the office of prime minister means, and shaped the office in their own image. After these ‘agenda changers’ ceased to be prime minister, their successors over the years that followed either tried to be like them, or tried deliberately to distance themselves from them: but none could escape their long shadow. They took advantage of wide-ranging historical or consensus change and moulded the office and country to their will.

Eight under-accomplishing premierships since Thatcher stood down in 1990, and a long list of long-standing domestic problems not resolved by successive administrations, including stalled productivity in the economy, crumbling transport infrastructure and chronic housing shortages, repeated failures to address social care and a failing health service, speak of a failure of leadership at the top. Many PMs – not all– who stepped up were potentially well-equipped for the job. So what has happened? Has the job now become impossible: or is it the quality of the incumbents and their preparedness for office that have declined? This final chapter seeks to provide answers. It probes the issue of quality, and examines which prime ministers have been successful and why, assigning them to one of six grades. It examines how judgements about premierships are formed, and the role of the individuals themselves in shaping those perceptions, before concluding with five proposals to ensure that, as we move towards the mid twenty-first century, prime ministerial performance might improve.

The country the different prime ministers have led and the political system over which they have presided have been vastly different. In this chapter, we explore some of the more momentous technological, political, cultural, and social changes that impacted on the office over the 300 years. Only by appreciating these factors, which have been perhaps under-considered in the literature on the office to date, can a rounded appreciation of the office’s survival it be achieved. The sheer pace and extent of these changes makes the continuity and survival of the office of prime minister over the full 300 years, and the adaptability of the individuals involved, even more remarkable.

By 2024, the prime minister had emerged as the dominant figure in control of foreign policy, taking over the powers initially from the monarch, then Parliament, then the Foreign Secretary. The prime minister decides British foreign relations, whether the country goes to war, and how it is fought. This chapter will examine how and why this transition occurred, and why the prime minister today can afford to be more preoccupied with foreign rather than domestic policy, and what this has meant to the office and powers of the prime minister – even in the face of war and increasing geopolitical tension.