Facebook’s bill was also less than the average personal income tax payment and the national insurance contributions that individual British employees pay, which amount to about $7,800 a year for someone making the median income of $40,000.

That is just one glaring example, Mr. Lewis and his fellow shopkeepers in Crickhowell said, of what amounts to multinational tax dodging on a gargantuan scale, leaving the little guy to pick up the tab. And their protest is one small case study of how economic populism is playing out around the world, rallying grass-roots support to challenge governments and corporate interests alike.

Mr. Lewis, who retired from the army as a major and fought in Northern Ireland and the Middle East, is working with his regiment of shopkeepers to stoke public indignation across Britain so that consumers, and ultimately shareholders, will pressure company executives to change the way they do business. He plans to use social media and doorstep protests to “name and shame” corporate chiefs and those who support them, right down to their tax accountants.