Supreme Court, Parliament Square SW1

The mouldings over the ground floor windows on the left hand side of the main facade of the old Middlesex Guildhall are decorated with figures connected with the River Thames. The old geezer with the trident must be fishing for eels, as then he would fit in with the rest of the trades, but Fehr has clearly taken the opportunity to make him do double duty as Old Father Thames.
From left to right:

Fishing with nets for salmon and trout

Kelping

Spearfishing for porpoise, seal and sturgeon

Woman with her hand on the bow of a boat

Fishing for eels (the trident is dug into the mud and the eels are trapped between the tines)

A fishwife takes fish to market.
As ever, let me know if you think I have got any of these stupidly wrong.