The day had been short, lit by a mocking sunlight that refused to admit Christmas cheer into its long black shadows. People now churn through the streets of the City, pushing home, diving here and there from the crowd to chance a last-minute bit of gift shopping. The dark evening barely intrudes in the continuous stream of headlights, streetlights and the bobbing rectangles of phone screens, frantically being consulted for opening times, stock levels, last trains.