I stuck on his flat blue hat and his white overall, picked up the cans, banged my door, and went whistling downstairs. The porter at the foot told me to shut my jaw, which sounded as if my makeup was adequate.

At first I thought there was nobody in the street. Then I caught sight of a policeman a hundred yards down, and a loafer shuffling past on the other side. Some impulse made me raise my eyes to the house opposite, and there at a first-floor window was a face. As the loafer passed he looked up, and I fancied a signal was exchanged.

I crossed the street, whistling gaily and imitating the jaunty swing of the milkman. Then I took the first side street, and went up a left-hand turning which led past a bit of vacant ground. There was no one in the little street, so I dropped the milk-cans inside the hoarding and sent the cap and overall after them. I had only just put on my cloth cap when a postman came round the corner. I gave him good morning and he answered me unsuspiciously. At the moment the clock of a neighbouring church struck the hour of seven.