A Lot of Bottle!

zerohour has asked for pictures of Trafalgar Square. She is interested in "how the space gets used. What goes on there? What gets put up? Anybody sits on the stairs to eat lunch? How do people move through the space? Street performers, exhibit posters, green walls (!), and such... I would be very grateful! If you happen to know of any good books that describe it, I'll take the titles, too :-)"
So on my lunch break today I braved a "Boris bike" for the first time & peddled over there.

The "forth plinth" was intended for a statue of William IV, after whom the Square originally to be named, but lack of funds meant it remained empty.
Since 1998 it has been used to temporarily display contemporary art.
"Ship in a Bottle" by Yinka Shonibare MBE, is the first commission to reflect on the historical symbolism of the Square, & also the first by a black British artist.
The ship is a model of Nelson's HMS Victory, the sails are made from patterned textiles associated with African dress. The fabric was originally inspired by Indonesian designs, made in the Netherlands & sold in the African colonies.
The work "considers the expansion in trade & Empire, made possible through the freedom of the seas Nelson's victory provided."

I'm not sure if this is really the sort of thing zerohour wants, but if you have any blips of the Square that might be useful to her, please sent her a link!