Hmm. The British do get around:
A new study has found that at various times the British have invaded almost 90 per cent of the countries around the globe.
The analysis of the histories of the almost 200 countries in the world found only 22 which have never experienced an invasion by the British.
Among this select group of nations are far-off destinations such as Guatemala, Tajikistan and the Marshall Islands, as well some slightly closer to home, such as Luxembourg.
The study does not seem to make a distinction between invasions and expedition where the host country invited the British. As far as I can recall the British never invaded Portugal, though British forces were certainly invited into the country on several occasions, the most famous being during the Peninsular War.