Mr Johnson risks ending up with “no friends around the world” because he has taken a path of confrontation with European allies, said the ex-prime minister.
It is in the UK’s economic interest to do a deal with the EU now, but the bare-bones treaty being sought by Mr Johnson was unlikely to end uncertainty, Mr Brown warned.
Speaking on Sky News’ Sophy Ridge on Sunday programme, Mr Brown said that Mr Johnson appeared to be hoping that German chancellor Angela Merkel will step in to break the deadlock at Thursday’s EU leaders’ summit.
“He always takes it to the last minute,” said the former Labour PM.
“If there is no deal now, I see huge international implications from what he fails to deliver, because we would be in an economic war with Europe that would cost us very dearly.
“Food, drugs and everything else we would find it difficult to get into the country without tariffs and without hold-ups.
“But we’d also be in an economic war with America because there’d be no chance of a trade treaty with America.
“And so, Boris Johnson is going to end up as the most isolated prime minister in peacetime history, with no friends around the world, because he has simply chosen a path of confrontation, when everybody knows that it’s in Britain’s economic interest – maybe not in the Brexiteers’ ideological interest, but in Britain’s economic interest – to get a deal and to get a deal now.”
Mr Brown declined to say whether Labour leader Sir Keir Starmer should back any deal in a Commons vote, saying he expected him to wait to see the details before deciding.
“One of the problems we have got is the difference between a no-deal and a deal is becoming quite slim,” he said.
“It looks as if what’s going to happen is they’re going to say ‘Yes we’ll have tariff-free trade, we’ll have quota-free trade, but the minute you breach the level playing field, we are reserving the right to impose tariffs and impose sanctions upon you’.
“So you may have an unstable relationship over the next few months or indeed over the next few years, because all they can get to in this negotiation is a minimalist deal, which leaves people very uncertain about the path of the economy.”
