Michael Gove, the education secretary, is confident his office will be cleared of leaking the documents that implicate Ed Balls in a plot to remove Tony Blair

Michael Gove, the education secretary, is confident his office will be cleared of leaking the documents that implicate Ed Balls in a plot to remove Tony Blair after Whitehall sources indicated that an internal Labour feud is behind the breach of security.

As the Cabinet Office released details of an investigation into the alleged leak from the education department, sources close to Gove accused Balls of demanding an inquiry to deflect attention from the Labour feuding.

A source close to Gove told the Guardian: "Like with [former Haringey council children's services boss] Sharon Shoesmith, Ed Balls is pathetically trying to blame officials. He should ask friends how these things got leaked."

Gove fought back after the cabinet secretary, Sir Gus O'Donnell, sanctioned an investigation into the leak in the early hours of Friday morning after a complaint from the shadow chancellor. Balls also contacted David Bell, permanent secretary at the education department, late on Thursday night after the Daily Telegraph published the documents. They show that Balls was the key figure in "Project Volvo", designed to unseat Blair and prepare Gordon Brown for the Labour party premiership.

Balls told the BBC on Friday: "The last time I saw them [the papers] was when they were on my desk in the [education] department. I don't know how they were taken and got to the Telegraph."

The papers were not among correspondence sent to his Commons office after the election, by which time Balls had stood down as education secretary. Bell formally ordered the inquiry after consulting O'Donnell.

Senior figures in Whitehall are highly sceptical of the shadow chancellor's claim that he left sensitive documents, including annotations by the then-prime minister, in a file on his desk in his department as he headed off to campaign in last year's general election. The formal explanation of the inquiry indicated that O'Donnell has not accepted Balls's the claim that the documents were in the department, let alone that they were then leaked by an official or someone from the office of his successor, Gove.

The prime minister's spokesman explained the investigation, saying: "The Cabinet Office is looking into, first, whether these papers were in the possession of any department. And second, if so, whether there have been any breaches of document security within government."

One Whitehall source said of the Balls complaint: "This all has a familiar ring to it. Ed Balls loves inquiries."

The source speculated that Balls may have leaked the documents himself. "This has the feel of desk-clearing about it. Ed Miliband is struggling a bit, Ed Balls must be eyeing up the Labour leadership. So why not get all this out on his terms so this stuff is not released at a more difficult moment?"

Gove and other senior Tories have a different view. They believe that a former member – or members – of the Brown circle leaked the papers to damage Balls at the moment that he is emerging as a pivotal figure in the Labour party.

Greg Hands, parliamentary aide to George Osborne, tweeted: "Worth noting how leaky Labour has become under the Two Eds, with a steady stream of docs seemingly from both their offices in the last year."

Balls insisted this morning that the documents, from 2005 and 2006, do not show that he was plotting against Blair. He told the BBC: "After 2004 and then on there was a discussion between Tony Blair and Gordon Brown and others, which included myself, about how we manage that stable and orderly transition. There was discussions, there was negotiations.

"I lived through these years. I know what happens when people allow personalities and debates and fights to get in the way of the national interest. I was part of trying to hold things together in difficult times. There are important lessons to learn, people want to know that the Labour party has learned them. We have, 100%. That is why we are not going to be diverted by these kind of false and mendacious allegations. The idea that there was a plot or a coup is untrue and not justified by these papers."

In an attempt to implicate the Tories in the leak, he said the publication was "an attempt to take attention away from what is going on in this country".