Big it up for the Museum of London Docklands, near Canary Wharf. You can go there on the DLR, always a bonus, which will counteract the queasiness you feel at proximity to a large number of bankers, accountants and lawyers.
Apart from any temporary exhibitions, the Museum offers a chronological account of the ports of London from Roman times to the present day; you start on the third floor and work downwards. The timeline anchors the narrative, but there is no attempt to pretend that there is a single uncontested history: conflicts over slavery, dock labour schemes and modern redevelopment are all presented, using a mixture of text, displays of artefacts large and small, models, paintings, audio and video. Easy to spend several hours there; the Docklands at War section was particularly interesting.
And if you have time afterwards, nip around to The Grapes for bangers and mash (£6.50) [or whatever you like] and a pint of Timothy Taylor’s Landlord, which (weather permitting) you may be able to consume on the balcony overlooking the Thames, with the shingle below on which the mudlarks worked, while you remember all those Conrad novels and sing “Sweet Thames flow softly” .