Why would you do this?

Last week saw the destruction, or possibly theft of a well known landmark in Wratten Road East, just off Tilehouse Street.

Located on the corner of these two roads the bell like marker has been uprooted either by design or accident. But, if by design how would it have been transported away with it being so heavy?

Since the incident happened the council have tarmacked over the location and the bell like marker is nowhere to be seen? But what is it? I have seen several of these over the years and they have always been on  the corner of roads. This particular one in Hitchin has always been vulnerable as I have seen several large vehicles struggle to turn in and out of this road with Tilehouse Street being so narrow and full of historic buildings.