Shawshank moment

Beneath a gherkin shadow,
is a building site of yellow jackets and
giant cement mixers tumbling their churning tummies.
Tower cranes swing chains that
slip like eels through the cold air,
unoiled hinges singing their sad song
calling out in a minor key
as far as the Square Mile can see.
Sharp-suited City boys look up, searching
for a source of this mournful call;
Boris bikes clunk to a pale blue halt,
their riders joining the collective gaze
and everybody stops for a Shawshank moment.
A police officer, biceps swelling under
regulation navy blue streaks out of a health food shop,
chocolate button eyes flicking up to the sky
as he hears the tower-crane-song.
His arms are full of plastic packets of nuts;
cashew, brazils, almonds and dried apricots.
He wrenches open a police van door,
sliding open my curiosity and throwing
packs of health snacks to his officer friends.
The van pulls away,
the tower crane cranks to a halt
and the song is done,
everyone moves on,
smartphones are whipped out as people
remember their business
and we keep on keeping on.