Just over 12 hours after May announced that her team of top ministers had agreed to the terms of the draft agreement, Brexit minister Dominic Raab and work and pensions minister Esther McVey quit, saying they could not support it.
Their departure, and the resignations of two junior ministers, shakes May's divided government. Raab is the second Brexit secretary to quit over May's plans to leave the EU, the biggest shift in British policy in more than 40 years.
By leaving now, some suggested that Raab could be positioning himself as a possible successor to May.
But the prime minister showed little sign of backing down in parliament, where she warned lawmakers they now faced a stark decision - choose to leave with no deal, risk Brexit never happening or back her deal.
"The choice is clear. We can choose to leave with no deal, we can risk no Brexit at all, or we can choose to unite and support the best deal that can be negotiated," she said.
She acknowledged that hammering out an agreement with her cabinet was not "a comfortable process".
But she told those lawmakers who believed she could get a deal that did not include a backstop arrangement to prevent the return of a hard border on the island of Ireland that they were wrong.
