London (CNN) British former Foreign Secretary Boris Johnson was criticized Sunday following comments he wrote in a British newspaper that referred to Prime Minister Theresa May's Brexit strategy as a "suicide vest."

"We have opened ourselves to perpetual political blackmail," he writes. "We have wrapped a suicide vest around the British constitution -- and handed the detonator to [EU Brexit negotiator] Michel Barnier," Johnson wrote.

In the article published in the Mail on Sunday newspaper, Johnson wrote that instead of striking a "giant and generous free trade deal," May says "yes sir, no sir, three bags full sir" to the European Union.

Johnson, one of the leading figureheads of the winning campaign to leave the EU, scheduled to happen in March 2019, is said to be poised to launch a leadership bid against May.

He resigned from May's Cabinet in protest at May's plans for a post-Brexit trading arrangement with the other 27 members of the bloc, known as the "Chequers" deal, because he believes it would mean the UK abiding by EU laws with no role in the decision-making process.

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