"POLITICS 2016" by ELISA CHIERUZZI, Giovanni Murolo is licensed under CC BY-NC-ND 4.0
Furious MPs blasted the uncertainty - saying the "wretched soap opera of Brexit continues" as the country heads "back to square one".
And Cabinet ministers were summoned for a crisis meeting at No10 to work out how to move forward.
Parliament has repeatedly voted against Mrs May's strategy for leaving the EU on March 29 - last night the Commons laughed and cheered after the the fresh chaos was confirmed.
But without a clear alternative on the table, the latest defeat opens the door to a range of wildly different outcomes - from a cliff-edge No Deal to a second referendum which could cancel Brexit entirely.
Tonight MPs will vote on whether Britain should quit the EU without a deal in 17 days' time.
But they are expected to oppose the idea - and will instead back a delay to Brexit in a further vote likely to take place on Thursday.
Tory MP Bob Seely, who voted for the deal, warned that last night's result would "prolong the Brexit purgatory" and "grab defeat from the jaws of victory".
He said: "This entire episode is becoming a shambles that reflects appallingly on this current House of Commons. There are now no good options."