You wouldn't get much milk or cream in this jug. It's only 2 and a half inches (6.3cm) high. I don't mind though, it's still a lovely example of hand-painted decoration from the 1950s.
This is Poole Pottery again (the Alpine White glaze and mushroom-coloured interior is a distinctive giveaway). The painted pattern is known as Feather Drift, which I think was designed by Alfred Read in the mid-1950s. The jug shape is from a range called Streamline, designed by John Adams in 1935-1936.
It would be nice to own a large vase or display charger in a pattern like this. But alas, they don't come along too often. In the meantime, it's a pleasure to admire the decorators art on little gems like this.