In an article in the Mail on Sunday newspaper, Johnson pressed his attack on May's so-called Chequers plan to leave the EU, calling it "a humiliation" that opens "ourselves to perpetual political blackmail," Reuters wrote.
May is under fire from all sides of the divisive Brexit debate, with Johnson, favorite to succeed her, leading a push by eurosceptic lawmakers for the government to "chuck Chequers" and pursue a clean break with the bloc.
But so far, May has signaled she will not drop her blueprint for Britain's future ties with the bloc after Brexit – the biggest shift in the country's foreign and trade policy for almost half a century.
"We have wrapped a suicide vest around the British constitution – and handed the detonator to (EU chief negotiator) Michel Barnier," Johnson wrote.
His words - particularly the reference to a suicide vest - drew condemnation from fellow members of the governing Conservative Party.
Alan Duncan, a minister at the Foreign Office, said Johnson's comments marked "one of the most disgusting moments in modern British politics".
"For Boris to say that the PM's view is like that of a suicide bomber is too much," he said on Twitter. "I'm sorry, but this is the political end of Boris Johnson. If it isn't now, I will make sure it is later."
Johnson resigned as foreign secretary over the Chequers plan, named after May's country residence where the government agreed proposals to maintain close trade ties with the EU in July, and has attacked it as making Britain "a vassal state".
The prime minister's plans have also been criticized by EU supporters for offering the "worst of all worlds".
Many of Johnson's supporters hope his increasingly vocal criticism of May signals that he will launch a leadership bid while other Conservatives suggest his Mail article was solely to distract attention away from his marital difficulties.
On Friday, Johnson said he had separated from his wife Marina Wheeler and that the couple would divorce.