Calling for any information about this gun point at Cromwell.A member of public, who obviously knew a great deal about this gun pivot, once alerted the lock keeper to its history. Unfortunately that person didn't leave any contact details.
What we think we know is that the metal pin fixed to the ground is the pivot for a gun (possibly a semi-automatic machine gun). It's likely to have been manned by either the home guard or the women's auxiliaries during Britain's wartime defence (the thinking being that the enemy could come up the River Trent and or other significant navigations so a series of defences were installed). We also believe that the nearby brick building is an associated munitions store.
Today it poses a trip hazard, and its hit the list for requiring protective action. One suggestion is to highlight it with some form of interpretation which will demonstrate how it may have been used and the importance of waterways defence during the war.
Surely there must be someone out there who knows more than this about the pin and nearby building (or, indeed, are you that person)? If you know anything we'd be delighted to hear from you.