The former foreign secretary launched his stinging attack on Mr Corbyn following a newspaper interview where the Labour leader sparked fury among Remain-supporting Labour MPs after admitting Brexit would go ahead if his party won a general election. Writing in The Guardian, Mr Miliband also blasted leading Brexiteers for singling out the government’s “incompetence” for the Brexit crisis.
He claimed the “promises of Brexit can never be squared” and urged Mr Corbyn to do more to battle the government’s Brexit plans.
Mr Miliband said: “The Labour leadership is not much better. Jeremy Corbyn’s Guardian interview has rightly caused a furore.
“He makes clear that his difference with the government lies in tactics not goals, personnel not principles.
“The assertion – it does not deserve to be called an argument – seems to be that a better atmosphere would get a better deal.
“But this is a confusion at best and a fantasy at worst.”
Mr Miliband resigned from parliament in April 2013 to start a new post as CEO of the New York-based International Rescue Committee.
His broadside against Mr Corbyn comes after the Labour leader insisted he would try to seek a better deal from Brussels rather before the exit date of March 29, 2019, rather than allow a second referendum.
Mr Corbyn said: “You’d have to go back and negotiate, and see what the timetable would be.”
But Mr Miliband was adamant a people’s vote on the Brexit deal was the best option for Britain.
He said: “A people’s vote is not an admission of defeat or a poke in the eye to those who voted leave.
“’Better safe than sorry’ is the right approach when buying a house, and so makes sense when making a momentous national decision.
“The alternative to a bad deal – the May plan – is not no deal.
“It is reported that five cabinet members can now see their way to supporting a people’s vote.
“They need to insist that preparations begin now.”
Mr Miliband also underlined that as Vladimir Putin and Donald Trump wanted Britain out of the EU “their interests are not our interests”.
He added” “We have no time to lose in getting to grips with reality, sloughing off the illusions that have held sway on right and left, and embracing a vision of Britain’s future that is positive, empowered, progressive – and European.”