Well! This week you were certainly intrigued and so many good guesses but no one got it. The image is of a padlock and key found in York dating from the Viking era during the Coppergate Dig – something I looked forward to seeing most summers now I come to think about it.
The barrel shaped lock is opened by inserting the key into the opening at the end. I think that the action of fitting the key compresses springs to release the shackle of the bolt. The lock is a high status item in its own right.
On balance, that seems like such an easy thihg to have spotted. How many got it, I wonder…?
No one contacted me with the correct answer – all the answers I received were well thought out but it’s only when you know what it is that it becomes obvious.