No date given but guess at c.1955 Man on the left is Derek Palmer who was in Derby Corporation Sewerage Department. They are probably using manhole lifting keys to allow the water into the sewer. It could be flooded from river of a burst main.

In the 1990's, when the railway bridge at Agard Street was demolished by dropping it onto straw bales, it caused a trunk water main to burst and a gas main as well.

from Derby of Yesteryear Facebook page.