This song, though it evolved to take on a wider meaning, including the common interpretation that it is a criticism of British politics and international relations, was originally about something much simpler.
In 1979, a British newspaper ran a headline that warned that, with rapid global warning, there was a risk that the Thames river might overflow and flood London. When Mick Jones found this out, he (in his own words) “flipped.” So the song is less about politics, and more about a fear of drowning.