Coals to Newcastle

Selling, carrying, bringing, or taking coal(s) to Newcastle is an idiom of British origin describing a pointless action.^[1] It refers to the fact that, historically, the economy of Newcastle upon Tyne in north-eastern England was heavily dependent on the distribution and sale of coal and therefore any attempt to sell coal to Newcastle would be foolhardy as supply would be greater there than anywhere else in Britain.^[1] Similarly, Newcastle, New South Wales (named after the British city) has one of the largest coal ports in the world, and hence it would also be meaningless to ship coals there.