The setting for "Umbrella Man" by Roald Dahl is London.
The main character, the "umbrella man," is a flim-flam man who swindles the narrator's mother out of a pound note by telling her that he is too fatigued to walk home and needs a taxi. He offers his umbrella in return for the taxi fare; the umbrella, he says, is worth twenty pounds. Finally, with the urging of her daughter, the mother agrees to give the man who seemingly offers his umbrella generously in payment for a one pound note, the taxi fare he supposedly needs.
However, after following the older man, the mother and daughter see that he has tricked them. For, he is in a pub guzzling "a treble of whiskey." And, afterwards, he goes to the coat rack and unhooks his coat, but while doing so, he steals an umbrella
...in a manner so superbly cool and casual that you hardly noticed anything at all, he lifted from the coat-rack one of the many wet umbrellas hanging there, and off he went.
After they seeing him scurrying around after having traded his umbrella for money, the mother and daughter realize that they have been fooled.