The civil service provides Ministers with several different types of support. As well as specialist policy teams, all departments have strategy and/or implementation units who help prepare and monitor departmental plans, always working closely with finance and human resources teams. And then there are communications teams as well as special advisers who provide political advice and support. Last, but not least, every Minister is provided with a small Private Office who help organise his or her diary and day-to-day communications within the department and wider government. Each Private Office is led by a Private Secretary or - in the case of Cabinet Ministers - a Principal Private Secretary supported by one of more Private Secretaries. This webpage provides links to sources of information about the way in which Private Offices work.
A short guide to working effectively with Private Offices is here.
More detailed but very readable advice is in Chapter 2 of Christopher Jary's Working with Ministers.
Ministers need to be able to trust their Private Secretaries to be loyal in defending their interests both inside and outside the department. Equally, departments need to be able to trust Private Secretaries to ensure that Ministers behave properly. This was neatly summarised in an exchange between Yes Minister's Jim Hacker and Bernard, his Principal Private Secretary:
Hacker: 'You mean', I enquired disbelievingly, 'that when the chips are down, you'll be on my side, not Sir Humphrey's?"
Bernard answered very simply: 'Minister, it is my job to see that the chips stay up!'.
Giles Wilkes summarised ministers' 'need for a network of clever insiders' in this way:
Bernard Woolley, the principal private secretary immortalised by Derek Fowlds in the BBC sitcom Yes Minister, is portrayed as knowledgeable but naive. I found the opposite to be true. The best private secretaries are politically savvy, well-connected and almost indecently relaxed, given their elevated sphere of action. My abiding memory of early meetings with the chancellor was of his excellent private secretary casually jotting down minutes, and later smoothing the edges of disagreement with his equally breezy opposite number. The great men and women of politics find such nameless fixers indispensable to their ascent.
An amusing - but also essentially accurate - speech by ex-Private Secretary Edward Bowles is here.
And this Private Office Handbook will give you a feel for the atmosphere within, and working practices of, a Private Office in the early 1990s. Much of the advice in the handbook will apply equally well today, although some of the detail is of course out-of-date.
There was a short-lived experiment in creating Extended Ministerial Offices which brought together the traditional private offices, special advisers and external appointees so as to provide a much wider range of support functions. The relevant Cabinet Office guidance is here. Further background to this somewhat controversial development is here.
The Institute for Government suggested a number of ways for Strengthening Private Offices in 2023.
Finally, almost all Ministers love the support that they get from the Private Secretaries, not least when travelling. Wartime Minister Harold Nicholson admitted that he had "found a new pleasure in life travelling with a Private Secretary. One just walks about in a fur coat and things get done".