JEREMY Corbyn has dismissed as "utter nonsense" fears that a Russian misinformation operation was behind the leak of documents that he hailed as evidence the NHS was up for sale.

However, when pressed the Labour leader declined to defend how Labour had obtained the documents detailing talks between the UK and US on a post-Brexit trade deal.

The 451-page unredacted report has been used as evidence by the Labour leader that the US wants its corporations to have access to the health service and is interested in hiking drug prices.

The dossier is now causing difficulties for Mr Corbyn after social media researchers at Graphika said there were similarities between the leak and a Russian misinformation operation.

The consultancy said the initial dissemination of the documents on online discussion site Reddit in October and subsequent sharing bore similarities to a campaign known as “Secondary Infektion”.

The Labour leader dismissed the allegations and suggested they were a Tory smear but he did not defend how the party got hold of the document when asked twice in an interview this morning.

"This is such nonsense, such utter nonsense. This is desperation by the Conservative Party," declared Mr Corbyn.

"Not even the Government has claimed they are false documents. They have challenged our analysis of them, they've challenged what we think they are trying to do on them but they haven't challenged the honesty of them," insisted the Labour leader.

The dossier was first made public in a heavily-redacted format after a Freedom of Information request by campaigners Global Justice Now.

The group has reportedly said it was contacted via email after Mr Corbyn showed the document during a televised debate alerting researchers to the uncensored documents on Reddit.

Graphika said the similarities are not enough to provide a "conclusive attribution" but that they were "too close to be simply a coincidence" and could be by the original actors or by mimics.

There was no suggestion the documents were fake or that Labour was aware they might have been obtained or shared by improper means.