This is more from the Epicure’s Almanack, referring to the original Billingsgate Market, in London’s East End, leading down to the Thames. In the age before refrigeration, this was the best place to buy a wide range of fish, fresh from the sea or river. There were stalls where they would boil your fish and you could eat it then and there:
“Early in the morning hasty breakfasts are made at one or two of the houses, in a superior style, to the fishmongers and salesmen, whose coffee or tea is served up in silver mugs. To these breakfasts strangers cannot gain admittance. During the season in Dark-house Lane, great abundance of Gravesend asparagus is exposed to sale at reasonable prices; as are also frequently fine mushrooms from the Kentish marshes. There were shops there where you could get your fish boiled and eat it on the spot.
“Billingsgate was also where boats were caught: so two public houses faced the river.
This is from 1817: “Dark House Lane, ‘the turning immediately joining Billingsgate to the west, contains a number of public houses used by watermen, fishermen, females and others; her, from the confined situation, candles are necessary all day, particularly in winter. As some of these houses are open all night, to accommodate persons waiting for the Gravesend boats, beds may be had for all, whether really going to Gravesend, or only pretending so to do. Strangers who act prudently will avoid the mixed company in a place like this, especially such as wish to escape the fangs of those called kidnappers, or East India crimps.” [ie be conned into signing up to sail to the east]