I have a UK penny from 1976 with what appears to be Nickel on one side, and some on the edge. It's not smoothly distributed over the face of the coin. Could this be a minting error or has someone tampered with it? Reaching out to all you folks for advice as I'm new to this.
When the 1p coin was first introduced in 1971, it was bronze all the way through. In 1992 they changed to steel plated with copper to save money. As your coin is 1976 it can't be some kind of flaw in the blank but something that happened after manufacture.