In the United Kingdom government, a Private Secretary (with capital letters) is a civil servant in a Department or Ministry, responsible to the Secretary of State or Minister. The senior civil servant in charge of administering the department is usually entitled the Permanent Secretary, and may also have a Private Secretary.
A Private Secretary (PS) is normally of middle management level; however, as the key official responsible for disseminating the decision of Ministers and indeed as their gatekeeper, his or her role is of considerably greater significance than this grade or level suggests. Depending on what level of politician the official works for they will be assisted by one or more Assistants - and or Deputy Secretaries, or even head a whole office in which those may be section chiefs.
For example, a Junior Minister may have a two person Private Office consisting of a Private Secretary and an Assistant Private Secretary. Whereas a Cabinet Secretary may have a 5 person Private Office consisting of a Private Secretary, two Deputy Private Secretaries and two Assistant Private Secretaries. The same applies to the Prime Minister’s Private Office but on a much larger scale.
Where the Private Secretary is a member of the Senior Civil Service, he or she will be referred to as a Principal Private Secretary, making the order of precedence Principal Private Secretary, Senior Private Secretary (rarely now in existence), Private Secretary, and Assistant Private Secretary (APS). A similar role to a Principal Private Secretary in the United States Administration would be a 'Chief of Staff'.
The Private Secretary is the principal link between a government Minister and officials in the Department or Ministry. He or she has overall responsibility for coordinating the development of the Minister's policy remit, ensuring that the aims of Ministers are clearly and fully implemented by the Department. In that respect a PS and APS will often be in a position of debate with colleagues of much higher seniority.
A PS or an APS is always in attendance with the Minister at every meeting or event to provide support and to ensure that a member of the UK civil service, who are non-political appointees, takes a factual note of discussions and commitments.
They also have ownership of the Ministerial diary, managing the Ministerial Diary Secretary whose task is to sift and prioritise invites, commitments, policy briefings and parliamentary business. A PS is always the initial source of advice to Ministers on parliamentary protocol, the process of cabinet business and departmental policy.
Often the APS and DPS will take on specific responsibilities within the Private Office such as dealing solely with correspondence or diary matters. They often deputise and support other members of the PO but would be considered subject matter experts for that area of work.
Working in Private Office as a Private Secretary or an Assistant Private Secretary is often seen as essential for advancement to the Senior Civil Service. Although considered to be a highly rewarding and sought-after post, it is one of most difficult when compared to others at the equivalent grade.
Depending upon the seniority of their political principal, a Private Secretary may him or herself be regarded as an important official in their own right; the Queen's Private Secretary and the Downing Street Private Secretary being the most important.
A Parliamentary Private Secretary (PPS) is a Member of Parliament appointed to act as unpaid assistant to a Minister. The PPS allows the Prime Minister, or minister, to reward party colleagues without cost, and test potential future ministers, and strengthens the Whip system as a PPS is expected to support the government's policies and vote for them in the parliament, regardless of their personal opinions.