Green’s Dictionary of Slang

long-tailed beggar n.

1. [mid-19C] a cat [the supposed story of a sailor who came home after his first voyage unable to remember the name of a cat and asked his mother ‘What’s she called, that ’ere long-tailed beggar?’].

2. [1900s–20s] a large denomination sterling note [long-tailed ’un n.].