Margery Allingham 
The Tiger in the Smoke 

GHOSTS “It may be only blackmail, ” said the man in the taxi hopefully. The fog was like a saffron blanket soaked in ice-water. It had hung over London all day and at last was beginning to descend. The sky was yellow as a duster and the rest was a granular black, overprinted in grey and lightened by occasional slivers of bright fish colour as a policeman turned in his wet cape.

Already the traffic was at an irritable crawl. By dusk it would be stationary. To the west the Park dripped wretchedly and to the north the great railway terminus slammed and banged and exploded hollowly about its affairs. Between lay winding miles of butter-coloured stucco in every conceivable state of repair.