From there rumours began to fly. Was "Jade" a reference to China and a Chinese takeover of the United States? Was "Helm" a nod to the blue helmets of UN peacekeepers, who are perennial boogiemen for those Americans fearful that the global body is trying to subdue US democracy?

One of the most persistent theories was that Walmart stores across the US were being closed so they could be used as secret staging locations for invading troops.

Chuck Norris, the ageing action star, also piled in, warning about "those who are pulling the strings at the top of Jade Helm 15 back in Washington".

The flames were fanned by the site InfoWars, which is run by Alex Jones, one of America's most prominent and prolific conspiracy theorists. In one video, he gave an "emergency broadcast" warning of the dangers of Jade Helm.

But what started on the internet soon began to seep into real life.

A spokesman for the US Special Operations Command addressed a community meeting in Texas in late April where he received a frosty reception from residents who peppered him with questions about Operation Jade Helm.

One man told the meeting he "didn't believe a word the colonel was saying" in an unusually direct challenge to a uniformed soldier in a country where the troops are treated with reverence.

It was Greg Abbott, the governor of Texas, who gave real credence to the conspiracies by ordering Texas national guard troops to "monitor" the US forces taking part in Operation Jade Helm.


The order was met with outrage even by some fellow Republicans. "Your letter pandering to idiots... has left me livid," one former Republican politician wrote to Mr Abbott.

But other Texas Republicans said they could understand their constituents fear of the Obama administration. "I understand a lot of the concerns raised by a lot of citizens about Jade Helm," said Ted Cruz, a Texas senator running for president, who added that he had asked the Pentagon for more information.

Josh Earnest, a spokesman for the White House, could only shake his head when asked about the governor's order. "I have no idea what he's thinking," he said.

Operation Jade Helm is due to begin in July and continue through September.

The Telegraph London