In a darkened room, he says he will seek to dispel the Western media's "manipulated truths."
The video, entitled "Lend Me Your Ears," shows Cantile wearing an orange jumpsuit, clothing similar to that worn by the three Western hostages who have been executed in previous ISIS videos.
The video, however, takes a different strategy to those previously released by ISIS regarding Western journalist hostages. This one features the journalist talking alone directly to camera. In videos showing the killing of journalists James Foley and Steven Sotloff, the journalists are shown reading scripted remarks as an apparent executioner stands next to them.
Cantile introduces himself as a journalist who's worked for British newspapers including The Sun and The Sunday Times, and says: "I know what you're thinking, he's only only doing this as a prisoner and he's got a gun to his head, he's being forced to do this."
He then says, "I am a prisoner, that much is true," and claims he is speaking out because he has "nothing to lose" after being "abandoned by his government."
The three-minute video did not suggest there was any immediate threat to Cantlie's life, but he did appear to speculate that that may not be the case in the long term.
Cantlie also implied this would be the first of several videos. "Over the next few programs, I'm going to show you the truth as the Western media tries to drag the world back to the abyss of a war with the Islamic State."
YouTube quickly removed the video.
Cantlie was first taken captive by rebels in Syria in July 2012, along with another British journalist, The Guardian reported. The pair were held hostage in a jihadist camp for nine days, before fighters aligned with the Free Syrian Army stormed the camp and secured their release.
After his release in 2012, Cantlie told The Guardian he was eager to return to Syria. "We'll see what happens, but this experience has only made me wiser. I'm desperate to get back into Syria and work alongside those gracious, hospitable people as they pursue their dreams of revolution. Lord knows they've earned it."
Once back in England, Cantlie helped to identify some of his alleged British captors to U.K. intelligence authorities. A subsequent trial against some of his alleged captors collapsed in 2013.
Cantlie could not testify at the case — because by the fall of 2012 he had already returned Syria, this time with James Foley. The pair was soon after kidnapped.