Brewer's: King of Dalkey
A burlesque officer, like the Mayor of Garratt, the Mayor of the Pig Market, and the Mayor of the Bull-ring (q.v.).
Dalkey is a small island in St. George's Channel, near the coast of Ireland, a little to the south of Dublin Bay.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894