I just knew that was coming
Yes, was hoping that it wouldn't come up on this forum but yes, "In the UK, the Coinage Offences Act 1936 prohibited the defacement of any current coins. This was repealed in its entirety by the Forgery and Counterfeiting Act 1981, thus removing the prohibition on coin defacement."
.... but imagine the YouTube video of his execution on Tower Hill - now that WOULD go viral
BillTodd, interesting suggestion, I think you would struggle getting a grip on such a small rim around the coin shell.
What would happen if it was tapped/hammered gently onto gradually increasing Mandrels so it sat on the end of each one like a cap. It would need tapping off and then moving to the next one. Or would it cause too much stress to the rim and rip it rather than stretch the material on the top/face of the coin.
Another thing, what about approaching it the other way. Could it be flattened I.e hammered, rolled or somehow increased in diameter and then bored and hollowed?