Now a busy shopping area, the width of this street is a clue to its former use, because this is the Corn Market; forerunner to the Derby Corn Exchange. Prior to the opening of the Corn Exchange building in 1862, this is where corn would be sold by local traders.
To attempt to answer Alan from News from Nowhere, my understanding is that the UK usage of corn covers a range of grains, as a generic title for cereal crops. My guess would be that the corn markets would also have sold animal feed as well as grains for breadmaking etc. Google isn't being overly helpful, but does that make sense?
Beyond the market place, Iron Gate runs steadily uphill towards Derby Cathedral; which reminds me - I must print out my registration form for the next abseil! :)