What is the British slang for piggy bank?

There isn't really a specific British slang term for a piggy bank. While "piggy bank" is used in Britain, it's not considered slang.

However, here are some informal or humorous ways to refer to a piggy bank:

* Money box: This is a common, informal alternative to "piggy bank".

* Money pot: This is a more poetic and whimsical term.

* Sparky: This term is less common, but sometimes used for a child's piggy bank.

It's important to note that slang can vary greatly depending on region and age group. What might be considered slang in one part of the UK might not be in another.