Can you tell what it is yet?

Out with New Manchester Walks for a tour of the Victorian side of Manchester (Victorian Pubs - ahem - of which there are a few unspoilt old boozers left)
We had a diversion in to the inner court yard of the town hall, which was full of photo opportunities. However......
One of the guests was studying this item with great interest, and caught me watching him. He asked, " what do you suppose this was for?"

Well, I couldn't deny my self this opportunity of educating such a keen young mind.

"In the old days when milk was first delivered in bottles, the bottom of the bottles couldn't be guaranteed to be flat, and the bottle would occasionally fall over, spilling milk in to these victorian cobble streets. (By now I had the audience). Children running to work in the mills in the early hours, would not get any milk with their gruel which was very upsetting, hence the saying "its no use crying over spilt milk".

So some genius in the borough engineers office, invented this to put the Milk bottles behind and stop them falling over."

I am still surprised by the number of heads nodding in collective agreement about such a splendid invention. The young mans curiosity was indeed satiated, and the Tour guide called me an evil Bugger. I wonder why ;-)