text: freedom to participate in public affairs consistent with that obligation. The rules are concerned with political activities liable to give public expression to political views rather than with privately held beliefs and opinions. 347. Certain civil servants are debarred from national politics, e.g. parliamentary candidature or speeches or articles in public on controversial national issues. In other cases this is permissible, or special permission may be given. Most civil servants can participate in local politics, although some must seek permission first. 348. Generally, there are no restrictions on the private activities of civil servants, provided that these do not bring discredit on the Civil Service, and that there is no possibility of conflict with official duties. For instance, a civil servant requires departmental permission before taking part in any outside activity which involves the use of official experience, or before accepting a directorship in any company holding a contract with his or her department. 349. People may not be employed in the Civil Service in connection with work that is vital to the security of the State if they: (a) Are, or have recently been, a member of a communist or Fascist organization, or of a subversive group, acknowledged as such by the appropriate Minister, whose aims are to undermine or overthrow parliamentary democracy in the United Kingdom of Great Britain and Northern Ireland by political, industrial or violent means; or (b) Are, or have recently been, sympathetic to or associated with members or sympathizers of such organizations or groups, in such a way as to raise reasonable doubts about their reliability; or (c) Are susceptible to pressure from such organizations or groups. 350. The diplomatic service and certain other posts in certain departments are closed to persons who are thought to fall within the above categories. 351. To ensure that persons employed in exceptionally secret work are reliable, 
analysis: The text appears to be discussing the rules and regulations surrounding the employment of civil servants in the United Kingdom, specifically in regards to their political activities, potential conflicts of interest, and security clearances. The focus is on ensuring the reliability and loyalty of civil servants, particularly in sensitive or secret roles.