While most of these things are moved inside at night, at many corner shops, news agents and kiosks, one large box remains outside.
In my neighbourhood, phone card advertisements are often affixed to these boxes. Alternatively, they are fashioned with metal and plastic frames used to display current magazine covers. In either case, they show the layering of stickers, paint, practice, wear and tear.
Their mystery was solved at the news agent on Euston Road. The keeper explained that his large blue metal box is used for early morning newspaper deliveries and as a place to deposit old papers and magazines.
Then he let me see inside.