The Labour leader unveiled the 451-page leak at a press conference in Westminster on Wednesday morning, saying Boris Johnson “tried to cover it up... but today it’s been exposed”.
But it appears the six documents comprising the leak were first made public on 21 October, when a Reddit user named “gregoratior” posted them to a politics forum on the social media site.
The Reddit post, titled “Official-Sensitive: Great Britain is practically standing on her knees working on a trade agreement with the US”, were only seen by a handful of users before Mr Corbyn came forward with them.
“I suspect that this publication will make some noise, so that’s why you probably don’t have much time to look through the internal secret documents that contain specific details of the upcoming FTA between the UK and the US,” the Reddit user wrote.
“Three years, six bilateral meetings of the UK-US Trade and Investment Working Group (TIWG), 12 chapter-level discussions, 451 pages of reports. A detailed analysis and processing of such an amount of material will require a lot of time, knowledge and definitely more than one pair of eyes, so I’m dumping this here.”
Reddit users commenting on the post today appeared confused as to how they missed it when it was first published.
"I can't believe this document has been sat on this thread for a whole month without us knowing," one user wrote.
Two days after the Reddit post, a Twitter user by the same name shared a link to it with journalists and members of the Labour Party, however once again it did not receive any noticeable attention.
On 22 November, Labour MEP Jude Kirton-Darling tweeted about the documents, however at the time it only received one retweet.
The Labour leader said the documents contradicted the Prime Minister’s denial that the NHS is part of negotiations with the US, which some fear could see parts of the public health service sold off to private US companies.
“This election is now a fight for the survival of our National Health Service as a public service free for all at the point of need,” Mr Corbyn said.
“So for the want of any doubt, let me give this reassurance: Labour will never ever treat our NHS as a bargaining chip in trade talks with anybody. We will never let Donald Trump get his hands on our NHS. Because our NHS is not for sale.”
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