The shadow business secretary told the prime minister to “stand up for the national interest” and strike an agreement with the EU rather than listening to Tory Brexiteers “who don’t want a deal”.
Miliband said no deal would be a “disgrace” given the UK is in the worst economic crisis for 300 years amid the coronavirus pandemic.
And he appeared to go further than Keir Starmer by suggesting Labour will back any Brexit deal the PM strikes with the EU, while stressing the party will want to “look at the detail” of the agreement.
“We’ve said we’re minded to support it,” he told BBC One’s Andrew Marr Show.
Miliband said no deal would be “disastrous”.
“What the government seems to be saying is we are willing to accept no-deal, which would mean tariffs across the board, because of some future, theoretical threat maybe sometime in the future to have tariffs in relation to some products.
“That makes no sense at all. That is like saying I’m worried that my roof is going to leak in five years’ time, so let’s bulldoze the house now.
“I say, no deal is a disastrous outcome for the country, it is not a wonderful outcome and it is a disgrace frankly that Boris Johnson said it.”
He added: “He’s being cavalier with our national interest and frankly he is playing Russian roulette with jobs and livelihoods of people up and down the country.”
It comes with Johnson and European Commission president Ursula von der Leyen expected to speak around lunchtime to make a decision on the future of negotiations.
Talks between UK chief negotiator Lord Frost and EU counterpart Michel Barnier went on until 9.30pm on Friday, with their technical teams continuing to midnight.
Johnson on Friday warned that no deal was now “very, very likely”.