Brexiteer Boris Johnson on Saturday lambasted British Prime Minister Theresa May's draft EU divorce deal, calling it a "historic mistake" of Titanic proportions.
Johnson used a speech at the annual gathering of the Democratic Unionist Party -- the day before a special EU summit to sign off the agreement -- to deliver a blistering attack.
"The Titanic springs to mind and now is the time to point out the iceberg ahead," said the former foreign minister, who resigned from the cabinet in July in protest at May's Brexit approach.
Johnson said that a contentious "backstop" plan for Northern Ireland, which if used would keep the British-ruled province more closely aligned with the EU in certain areas after a 21-month transition period, would leave it "an economic semi-colony" of the bloc.
"No British Conservative government could or should sign up to any such arrangement," he said.
He and the DUP -- the Northern Irish party whose support is vital to May's government and EU exit plans -- have pledged to oppose the deal when it comes before the UK parliament next month, where May faces an uphill task to get it passed.
The DUP's 10 MPs have propped up May's government ever since she lost her parliamentary majority in a disastrous 2017 snap election.