A mischief-maker known as the “Filipino Monkey” who listens in on ship-to-ship radio traffic in the Gulf and jams the network with obscenities and threats might have been behind the “bomb warning” that nearly triggered a military confrontation between the US Navy and the Iranians last week.

The Pentagon admitted that it was not sure where the voice had come from and could not confirm that the threat had emanated from one of the five Iranian Revolutionary Guard speedboats approaching three US warships at speed in the Strait of Hormuz.

However, the coincidence of the hostile-looking gunboats closing in on the three warships from the US 5th Fleet and the shouted warning, “I am coming to you, you will explode in a few minutes”, was considered too dangerous to ignore. The commanding officers of the destroyer, cruiser and frigate prepared to issue orders to open fire.

Tehran denied any such aggressive intent, despite angry statements from the Pentagon and the White House. Now the new theory, if proven, could lead to red faces in Washington.

The revelation that a hostile prankster has been breaking into radio traffic for years and heckling ship commanders has emerged in the Navy Times. Could it be the so-called Filipino Monkey who nearly provoked a shooting match on January 6?

Rick Hoffman, a retired US navy captain who commanded the cruiser USS Hue City, and spent many of his 17 years at sea in the Gulf, told the Navy Times: “For 25 years there has been this mythical guy out there who, hour after hour, shouts obscenities and threats. He could be tied up pierside somewhere or he could be on the bridge of a merchant ship.” Admiral Gary Roughead, Chief of US Naval Operations, admitted to the internal navy paper: “Based on my experience operating in that part of the world, where there is a lot of maritime activity, trying to discern [who is speaking on the radio channel] is very hard to do.”

The voice issuing the warning sounds different from the one belonging to an Iranian officer shown speaking to the US cruiser, USS Port Royal, from a small open boat in the video released by the Iranian authorities.

The Iranian officer is shown in a radio exchange asking the US warship to swap channels from the normal bridge-to-bridge Channel 16 to another frequency.

Mr Hoffman said that radio signals could travel long distances in that part of the world. “Under certain weather conditions I could hear Bahrain from the Strait of Hormuz [which leads into the Gulf waterway],” he told Navy Times.

The Filipino Monkey, he said, aimed much of his most obscene tirades at women in the US Navy whenever they went on the radio.

Another former commanding officer of a cruiser who spoke anonymously to the paper said he guessed that the prankster might have been behind the threat when he heard the audio message.

“There’s all kinds of chatter on Channel 16. Anybody with a receiver and transmitter can hear something’s going on. It was entirely plausible and consistent with the radio environment to interject themselves and make a threatening comment and think they’re being funny,” he said.

He added: “It’s a tough environment. You’re bouncing around, moving fast, lots of wind and noise. That sounded like somebody on the beach or a large ship going by.”

Commander Jeff Davis, a navy spokesman at the Pentagon, said he could not confirm whether the voice belonged to the Filipino Monkey. “It’s an international circuit and we’ve said all along there were other ships and shore stations in the area,” he said.

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