Buggins's turn

Etymology
Earliest recorded use is by Admiral Fisher, later First Sea Lord, in a 1901 letter.

'Buggins' is a humorous invented surname, suggestive of a man of mediocre ability.

Noun

 * 1)  A humorous, disparaging term for the appointment of a person by rotation or promotion, on the basis of length of service (it being that person's "turn") rather than merit or level of qualification.
 * He will be appointed on the principle of Buggins's turn.
 * 1) * 1919, Memories, John Fisher (reprinting a 1917 letter to him from an unnamed Privy Councillor)
 * I remembered your old saying "Some day the Empire will go down because it is Buggins's turn."'