The relationship between Ministers and Civil Servants, in constitutional terms, depends on a view of the separation between politics and administration, similar to that found in Weber’s theory of bureaucracy.
Ministers come into Government with a manifesto on which they have been elected and which they will want to see carried out. Civil servants seek to do this but will point out the problems with proposed policies.
Ministers decide issues in the light of advice from civil servants.
The Northcote-Trevelyan reforms, proposed in the 1850s, gradually led to a civil service appointed as a result of competitive examinations, rather than be the patronage of influential people as before.
Unlike officials in local government, who are appointed on the basis of technical expertise in areas such as traffic engineering or education, civil servants were seen as experts in administration itself.
Their job was to look at potential policies and work out the advantages and disadvantages of each in an impartial way and then put these arguments before Ministers who would decide what course of action to take
Once Ministers had taken a decision then the civil service would see that it was implemented through Government Departments.
Because of their impartiality, civil servants would be shielded from public scrutiny and attack and Ministers would take the responsibility for decisions in public and before Parliament, as part of the doctrine of Ministerial Responsibility.
The voters would judge their success at the next general election.