ashtray on a motorbike 

Used to describe something utterly useless.

This app is about as much use as an ashtray on a motorbike. Bloody thing crashes every time I try to make a purchase.

ashtray on a motorbike by immediate 1 August 26, 2019

as much use as an ashtray on a motor bike 

Useless i.e. Northern English slang, especially in Yorkshire because an ashtray would lose its contents if placed on a moving motor bike

He's as much use as an ashtray on a motor bike

as much use as an ashtray on a motor bike by PaulineH March 12, 2014