“The Cabinet Office, like many important British institutions that wield considerable power, is hardly known about outside. It is only the initiates who fully appreciate how powerful it is.” – Peter Hennessy

This month marks one hundred years since the role of Secretary to the Cabinet was created and the Cabinet Office was established. Lloyd George had replaced Asquith as Prime Minister. On taking office Lloyd George was determined to shake up the conduct of the war effort and as part of that work he decided that the way government itself was run was wholly inadequate.

1916 had been a wearying year for the British war effort. There were two particularly important battles at the Somme and at Jutland – neither engagement had been lost, but like so many battles of World War One, neither had quite been won. Britain’s energy, if not its resolve, was being worn down. As Lloyd George settled into Number 10 that winter of 1916 he knew he had to change the way Britain conducted itself at home and overseas. Britain’s war effort was struggling. Victory was not in sight. The price in blood and treasure was mounting. The United States was resolutely neutral and would not enter the war until nearly a year and a half later in April 1917. Exhausted physically and politically the Liberal Prime Minister H.H. Asquith had been forced out of No 10 and replaced by Lloyd George. It was Lloyd George who identified the weakness at the heart of the centre of government and sought an effective remedy.

‎War with its terrible pressures, demands, necessities and focus often brings greater advance in innovation and initiative than the less demanding periods of peace. Time and again it is possible to trace great strides in medical practice, technology, manufacturing and production to wartime initiatives. Public administration is no exception. Lloyd George’s solution was the creation of an office that could coordinate the work of government.

Based at 70 Whitehall the Cabinet Office sits at the heart of government both literally and figuratively. No 70, the large building it occupies on Whitehall dominates the entrance to Downing Street and physically holds its own with the much better known, larger and much more ornate buildings housing the Treasury and the Foreign Office. Number 70 looms over No 10, like a great shield, or barrier depending on your perspective, between the Prime Minister and the world beyond. Its very proximity to the head of government gives the Cabinet Office its unique aura of power.

Since being established by the first Secretary to the Cabinet, Sir Maurice Hankey, there have been eleven Cabinet Secretaries. In that time twenty-two Prime Ministers have come and gone. Set up as a wartime contingency, the post of Cabinet Secretary and the Cabinet Office have proved to be remarkably resilient and adaptable. No Prime Minister today would think of abolishing either the role or the department.

Hankey, who served in the role as Cabinet Secretary for twenty-six years, was the first in a series of remarkable men (no woman has yet held the post) to serve as Britain’s most senior civil servant. Some, but not all, have combined the role with that of Head of the Home Civil Service. It is a pairing of two remarkable and formidable responsibilities which when performed effectively give the holder a unique influence over the whole of government and its machinery.

Different Prime Ministers have used the Cabinet Secretary and the Cabinet Office in different ways. In a series of remarkable interviews for the Mile End Group, several years ago, the living Cabinet Secretaries – Robert Armstrong, Robin Butler, Richard Wilson, Andrew Turnbull, Gus O’Donnell and Jeremy Heywood – spoke very openly about the role and the responsibilities they fulfilled. These interviews, conducted by Peter Hennessey and Anthony Seldon, are well worth watching. They are not just for students of public administration because they give a real insight into how the centre of government is conducted and how that process changes with each Prime Minister. They should be of interest to everyone who cares about how government is conducted and politics works.

Each Cabinet Secretary talks of the importance of good Cabinet government, using the cabinet committee structure effectively, and of the importance of a professional and impartial civil service. But the interviews reveal the importance of the role the personality of a Prime Minister plays in how the centre of government functions and how it impacts on the quality of the decisions that are made. For example, it emerges quite clearly that where Mrs Thatcher was punctilious in using the decision making structure both in full Cabinet and its committees, Tony Blair was not.

From Richard Wilson onwards there emerges a perhaps unhealthy pre-occupation with the media. What is clear is that the longer they serve, the more a Prime Minister comes to appreciate their Cabinet Secretary and the resource the Cabinet Office offers to them.

Since the Nothcote-Trevelyan reforms of the mid Nineteenth Century Britain has been fortunate to have an effective and politically neutral administrative class serving those responsible for delivering government. Its efficiency and effectiveness ebbs and flows like all institutions but its values are timeless and important. At the centre of that system sits the Cabinet Office.

Traditionally the four great departments of State are considered to be HM Treasury, Home Office, Foreign & Commonwealth Secretary, and Prime Minister. Although the Cabinet Office would not claim promotion for itself, and would probably dispute the idea it is a department at all, it is perhaps time to add it to this list.