The British Empire was the most extensive empire by area. The area of the empire at its territorial peak was 35.5 million square kilometers (13.7 million square miles). British Empire has invaded about 90% of the countries around the earth.
The map below shows territories that were once part of the British Empire.
But if we take subdivision territories that were under British control is much more significant. Reddit user Dodolulupepe created a comprehensive world map of everything England or Great Britain has ever owned, colonized, invaded, visualized, occupied, etc.
The resulting map below illustrates the countries that, to one degree or another, faced the British Empire’s army will look as follows.
Thus, only 22 nations were never invaded by the British: Andorra, Belarus, Bolivia, Burundi, Central African Republic, Chad, Congo, Guatemala, Ivory Coast, Kyrgyzstan, Liechtenstein, Luxembourg, Mali, Marshall Islands, Monaco, Mongolia, Paraguay, Sao Tome and Principe, Sweden, Tajikistan, Uzbekistan, Vatican.
To learn more about the Britain Empire have a look at: