This is a nice earlier 20th-century Whisky advertising jug - made James Greene & Nephew Ltd.
It is 12 cm in height (5 inches). It is 8.3 cm square (3 1/4 inches).
It has the maker's mark to the base: James Green & Nephew Ltd Designers & Manufacturers London. Rd No. 342349
It features the famous Johnnie Walker "Striding Man" motif - he appears twice on the jug - on opposing sides.
This jug would have sat on a bar in a public house and contained water to water down your wee dram.