Gentleman's Relish is a type of anchovy paste. It is also known as Patum Peperium.
It was created in 1828 by an Englishman called John Osborn. It has a strong, very salty and slightly fishy taste, and contains anchovies (minimum 60%), butter, herbs and spices. Today, the secret recipe is withheld from all but one employee at Elsenham Quality Foods in Elsenham, England, the licensed manufacturer.
In Angela Thirkell's "Summer Half" the Gentleman's Relish sandwiches made by Kate, specifically for adults attending the river picnic, are instead wholly consumed by three adolescents, one of whom makes up a rude rhyme to "Patum Peperium."
In Ian Fleming's book, For Your Eyes Only, it mentions that at the time of the visitors, Mr and Mrs Havelock were having Patum Peperium sandwiches.
In Kim Cooper's novel, The Kept Girl, the author Raymond Chandler makes up with his wife Cissy over a gift of toast spread with Gentleman's Relish.
In the BBC's Monarch of the Glen there is mention of "Kilwillie Gentleman's Relish" as a product line for supporting the namesake's estate.
The period television series Mr Selfridge, mentions Gentleman's Relish in Episode 3, when Lady May asks a waiter for a "flavorful, personal" enhancement to a bland chicken dish.
Peep Show Series 3, Episode 5 has the following exchange:
Mark: Had a hard day Jeremy? Watching kids TV and eating kids cereal?
Jez: Why, what should I be eating, Gentleman's relish with olive?
It has been used as the name of a group of young men who hung around together at university, with homosexual overtones, in Robertson Davies' book, The Rebel Angels.