My earliest recollection of milk delivery must have been around 1908. It was of a man coming to our door bringing a large can of milk with two measures hung from the side: a pint one and a half-pint one. He then emptied one or more of these measures into our own jugs, which were metal with spring lids.
This milkman called at the house twice a day, first early in the morning and again later on. In hot weather he came more often.
Our milkman had a horse and cart, although some roads had milk deliveries by handcart. The horse and cart always reminded me of drawings of Queen Boadicea's war chariot, high in front where the reins of the horse rested, then graduating to lower towards the back. The back was about a foot from the ground so that the milkman could easily step off to serve customers. He carried milk churns with him, and his schoolgirl daughter helped him with the rounds.
Although everything looked clean to the naked eye, hygiene was unheard of, and no doubt there were plenty of germs on that large can that went from door to door. Perhaps this was one reason why the milk would go off so quickly, although lack of fridges, sterilisation and pasteurisation would have contributed.
There were inspectors, who would come round to test the milk. This was very necessary before the advent of sterilised and sealed bottles. It was well known that some milkmen would add water to their milk. I remember hearing my father say while reading the local paper, "Old so-and-so has been prosecuted again for adding water to the milk". I even heard it said that some milkmen topped up their milk from the local pond.