Lord Kinnock tried to call for an end to "sniping from behind'' at Ed Miliband from disgruntled Blairites, mocking them for wanting to take the party back to the "day before yesterday".
The former Labour leader, who famously welcomed Miliband's election as Labour leader by telling activists that "we've got our party back", said jibes from fellow Labourites were a "distraction'.
This comes after Alan Milburn, Tony Blair's former health secretary, told the BBC that Miliband was making a 'fatal mistake' by failing to champion NHS reform, and that his strategy was a "pale imitation" of Lord Kinnock's doomed 1992 election campaign.
John Hutton, another minister under Blair, later teamed up with Milburn to aim a broadside at Miliband over his reluctance to defend the last Labour government's economic record.
In an article for the Financial Times, they wrote: “If Labour is to win in May, the two Eds need to set the record straight and reclaim ground foolishly bequeathed to their opponents.”
John Prescott, Blair's former deputy prime minister, responded to Milburn and Hutton on Twitter by describing them as "Tory collaborators”.
Lord Kinnock told the Times that he had received messages from Labour figures about Milburn's swipe "to the effect of asking, ‘doesn’t he know we’ve got an election on?’ — in much the same spirit as people used to say, ‘don’t they know there’s a war on’?”
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The Labour peer's defence comes as a former health adviser to Blair warned that funds from Labour's flagship "mansion tax" that were meant to pay for thousands of doctors and nurses would take two years to materialise.
Paul Corrigan also accused Andy Burnham, Labour's shadow health secretary, of planning another “top-down reorganisation” of the NHS. In response, Labour said that Corrigan had misunderstood the proposals, saying the reforms would be a “local process” and that revenues would arrive sooner than he suggested.