Senior figures in the Labour Party say the older Miliband, whose leadership ambitions were thwarted when Ed Miliband won the Party vote, is simply 'waiting for his brother to fail.'
At which point David Miliband will resurrect his leadership bid.
In a new book, Ed: The Milibands and the Making of Labour Leader, David effectively accuses his 'ruthless' sibling of lying about he way he took the party leadership.
And the authors Mehdi Jasan and James Macintyre claim Ed Milliband's 'last minute' decision to stand was in fact the result of years of scheming and plotting.
One un-named Labour MP told the Sunday Times: “Ed Balls (the shadow Chancellor) and his closest allies have contempt for Ed Miliband.”
Another added: “It's not quite Cain and Abel but it can't be doing the party any favours.”
The same newspaper also publishes a damning poll showing more than 50 per cent of Labour voters do not know what their party stands for.
But this afternoon David Miliband released a statement saying: "I stand fully behind him and so should everyone else."