The Permanent Secretary, in most departments officially titled the Permanent Under-secretary of State or PUS (although the full title is rarely used), is the most senior civil servant of a British Government ministry, charged with running the department on a day-to-day basis.
Permanent Secretaries (known by other names in some departments; see below) are the non-political civil service heads (and "accounting officers") or chief executives of government departments, who generally hold their position for a number of years (thus "permanent") at a ministry as distinct from the changing political Secretaries of State to whom they report and provide advice.
When Lord Grey took office as Prime Minister of the United Kingdom in 1830, Sir John Barrow was especially requested to continue serving as Secretary in his department (the Admiralty), starting the principle that senior civil servants stay in office on change of government and serve in a non-partisan manner. It was during Barrow's occupancy of the post that it was renamed “Permanent Secretary”.
Permanent secretaries are the accounting officers for departments, meaning that they are answerable to Parliament for ensuring that the department spends money granted by Parliament appropriately. Permanent secretaries are thus frequently called for questioning by the Public Accounts Committee and Select Committees of the House of Commons. The permanent secretary usually chairs a department's management board which consists of executive members (other civil servants in the department) and non-executive directors.
Some larger departments also have a second permanent secretary who acts as deputy. In the early 1970s, in a major reorganisation of Whitehall, many smaller ministries were amalgamated into larger departments. Following this reorganisation, virtually all departments had second permanent secretaries for a time, though this is no longer as common.
The most senior civil servant is the Cabinet Secretary, currently Sir Jeremy Heywood, but the Head of the Home Civil Service is Sir Bob Kerslake who is also Permanent Secretary of a department. The holder of this office is distinct from other officials of permanent secretary rank within the Cabinet Office. By convention, the Prime Minister is Minister for the Civil Service and as such makes regulations regarding the service and has authority over it. These duties are delegated to the Minister for the Cabinet Office.
Permanent secretaries are usually created a Knight or Dame Commander of the Order of the Bath after five or more years of service in the grade or on retirement if not already holding the title (although the Permanent Secretary of the Foreign and Commonwealth Office will be created a Knight or Dame Commander of the Order of St Michael and St George instead). The most senior permanent secretaries, such as the Secretary of the Cabinet, may be created a Knight Grand Cross of the Order of the Bath, and even be given a life peerage after retirement. For salary comparison purposes, the permanent secretary is deemed broadly equivalent to a General and to a High Court judge.
Current UK permanent secretaries 
Outside the UK 
In some countries of the Commonwealth of Nations, the popular term for the equivalent position is now “Principal Secretary”.
In Australia, the position is called the "Departmental Secretary", “Secretary of the Department”, or “Director-General of the Department” in some states and territories.
In Germany, the equivalent office is called Staatssekretär (state secretary).
In Hong Kong, heads of policy bureaux, i.e., Secretaries, were filled by civil servants until their titles were changed to Permanent Secretaries in 2002, when political appointees filled the positions of secretaries under the second Tung Chee Hwa government. Since August 2005, the Office of the Chief Executive also has a permanent secretary. His ranking is, however, lower than most other permanent secretaries according to the pay scale.
In the Republic of Ireland, the position of "Secretary-General" of a Department is almost identical to that of a Permanent Secretary in the British Civil Service, with the exception that since the introduction in the mid-1990s of the Strategic Management Initiative, the post is no longer permanent, but carries a seven year time limit. This coincided with the introduction of the change of title from the previous title of “Secretary”. Irish government departments may also have a “Second Secretary”, which is equivalent to the Second Permanent Secretary grade in the British Civil Service. See also Civil service of the Republic of Ireland.
In Italy the highest Civil Service official in a Ministry or Department is either a Segretario Generale (Secretary-General) or a Direttore Generale (Director-General), while the position of Sottosegretario di Stato (Under-Secretary of State) is a political one and ranks below the Ministro Segretario di Stato (Minister-Secretary of State, the head of a Ministry or Department) or the Vice Ministro (Deputy-Minister), both political posts as well.
In New Zealand, the civil service head of a ministry is ordinarily entitled “Chief Executive”, though there are still some positions which still carry the title of Secretary (Secretary of Education, Secretary of Justice, Secretary of Transport). In some cases (such as the New Zealand Security Intelligence Service, Ministry for Primary Industries, Department of Conservation, Ministry of Health) the title is “Director-General”. Organisations with enforcement powers, such as the Inland Revenue Department and the [[New Zealand Police]) are headed by commissioners. The New Zealand Customs Service is headed by the Comptroller of Customs. Civil service heads are officially employed by the State Services Commission, further separating them from the politicians who hold ministerial positions.
In Singapore, Permanent Secretaries have to retire after a 10-year term even if they are younger than the official retirement age of 62 in Singapore, starting in 2000 when the Public Service Leadership scheme was introduced. This is to provide opportunities for younger officers from the Administrative Service – the elite arm of the Civil Service – to rise up the rank.
In Sri Lanka, the post of Permanent Secretary is the civil service head of the ministry. Normally referred to as Secretary, non civil service, political appointees are regularly appointed.