By ROLAND KELTS

I was looking for a light blue raincoat. The bulbs were dim and the ceilings low.  At Heathrow Airport’s Passport Control Center, the line of my fellow arrivals amassed in clumps, passengers slouching and scratching away the hours of cramped flight, fingering their cell phones and sleepily eyeing watches. There were browns, blues and starched whites—sweaters, jerseys, overcoats and t-shirts. But no light blues. Not a raincoat in sight.