Vegans and vegetarians are calling on the Bank of England to scrap the new £5 note after it was revealed to contain traces of tallow, a substance made from animal fat often used in soap and candles.
Responding to a question on Twitter, the UK's central bank confirmed that the notes does contain it.
The news sparked outrage among vegans and vegetarians, leading to the creation of a petition calling on the Bank of England to remove tallow from the new polymer notes, released in September.
Tallow comes from beef but fat can be rendered from deer, sheep, bear and other animals.
It is commonly used in cooking (frying and baking), as a lubricant, as a biofuel, for candle making and also skin care.
However, there are also traces of it in the polymer the Bank of England has used to make the new £5 banknotes.
The polymer has been supplied by Innovia Security - one of two companies worldwide who produce it for bank notes.