Britain’s former Brexit minister says Prime Minister Theresa May’s approach to the nation’s exit from the European Union is “a dangerous strategy.”

David Davis stepped down from his post Sunday. In a resignation letter, Davis told May that her plan to create “a common rulebook” that would abide by the EU’s rules on free trade would leave Britain in — at best — “a weak negotiating position, and possibly an inescapable one.” He said the plan would make the idea of reestablishing British sovereignty from the EU “illusory rather than real.”

May’s Cabinet agreed to her plan on Friday after a contentious meeting at Chequers, the prime minister’s official country retreat. Davis and some Cabinet members have advocated for a clean break from the EU, while others support a so-called “soft Brexit” that would maintain economic ties with the bloc through its customs union and its single market.

In an interview Monday on BBC, Davis said that May had allowed her negotiators with the EU to give away “too much, too easily.” But he said his resignation does not mean he will mount a leadership challenge to May.

Hours after Davis’ interview, May announced that Dominic Raab, a former housing minister, would succeed Davis as Brexit minister.