Gunman's Bluff by Edgar Wallace

At the appointed hour Mr. Connor arrived, paid off his taxi short of the bridge across the Serpentine, and strolled down toward the water. The night was inclined to be rainy; a high, chill wind was blowing -- it was not a night even for the most romantic of couples to spend on the brim of the Serpentine.

Mr. Connor was not romantic; he was very much a realist. He could well understand Margaret Maddison's reluctance to come to his wharf, and he blamed himself for the stupidity of such a suggestion. She might have come accompanied by the police, as the Gunner suggested she would; and that was exactly the way she would have arrived had she intended making a fuss.