The British history suggests that Tom Collins was created in London by Barman John Collins around the middle of XIX century. If made with Old Tom Gin, presumably becomes the Tom Collins. The first published recipe appeared in the manual of Jerry Thomas in 1876.
1 ½ oz Old Tom Gin
1 oz Lemon Juice
½ oz Simple Syrup
Fill Soda water
It is prepared by the technique Build in an Old Fashioned