The Telegraph today published a series of documents including letters said to have been sent between former prime ministers Tony Blair and Gordon Brown, revealing what the newspaper called “the extraordinary rift at the heart of Labour”.

The cache of documents show for the first time Mr Brown’s feelings towards Mr Blair in his own words and handwriting, material which has previously only been the subject of speculation and second-hand reports from anonymous sources.

In its report on the contents of the files, more than 30 memos reportedly belonging to Labour MP and former education secretary Ed Balls, the Telegraph accuses the MP of being involved in a “plot” to overthrow Blair, an allegation which he told the BBC today is “not true”.

Look I’m not going to deny to you there weren’t tensions, there weren’t arguments. It was hard during that period … But the allegation there was a plot, that there was nastiness, brutality, is just not true. It’s not justified either by the documents themselves or by what was actually happening at the time.

The Cabinet Office has since confirmed it is looking at whether the particular set of papers was in the possession of any government department, and only then would it look at whether a breach had occurred. Following this announcement the Guardian reports that education secretary Michael Gove said he was “confident his office will be cleared”.