If there’s a successful vote of no confidence on the sitting government May has no choice but to call for elections and dissolve the parliament. So no matter if May doesn’t want to call for elections, she is legally obligated to do so with a no confidence vote.
CC
exactly right. The scale of her defeat on the Brexit vote isn’t what will force her from office. It’s the vote of no confidence that follows will do the trick, if it goes that way.
The rules on this have changed since the Fixed Term Parliaments Act of 2011. If a sitting government loses a vote of confidence it then has 14 days to try to form a new government (such as a coalition). There must then be a second vote of confidence. If this is again lost, Parliament must be dissolved and a new general election called.