The Prime Minister needed to secure at least 159 votes and did so by fending off a rebellious group of 117 MPs to obtain 67% of the overall vote.
Her victory on Wednesday means that Conservative Party members can not try to oust May as their standard-bearer in the next year.
"Richard Buxton, head of United Kingdom equities at Merian Global Investors, said: "[May] is so "on the ropes" that I can not really see winning the confidence vote at this juncture helping very much; in 24 hours, in all probability, this will be little more than old news, and will do little, if anything, to change the EU's negotiation tactics". If Theresa May wins she can not face another such vote for at least a year. He said: "I think that it is very hard to support the deal if we don't get changes to the backstop".
May said she had been heard on the backstop: "No one that I met yesterday is in any doubt about the strength of concern in this house on this issue of the duration of the backstop".
It was a rare chink in the armour of a prime minister praised by her supporters as resilient but accused by her critics of ploughing on oblivious to the changing circumstances around her.
Conservative MPs don't like the concept of the "backstop" much at all, but they particularly don't like the fact that it would apply European Union laws and regulations to Northern Ireland (and to a lesser extent, the rest of the UK), and that the United Kingdom would need European Union permission to exit the "backstop" if and when it ever goes into effect.
Labour has said that it will table a no-confidence motion in Theresa May's government that all MPs - not just Conservatives - will be able to vote in - but only when they felt they had a chance of winning it, and forcing a general election.
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Home Secretary Sajid Javid tweeted that a leadership contest, with Brexit little more than three months away, "will be seen as self-indulgent and wrong."Justice Secretary David Gauke said: "I think it's vital for the country that she wins tonight."He said that if May lost, "I don't think we will be leaving the European Union on the 29th of March".
The British Pound rallied through the mid-week session as markets bet that the no confidence vote called in Prime Minister Theresa May would ultimately prove unsuccessful and see her potentially strengthen her hand.
May spoke to dozens of Conservative lawmakers ahead of a no-confidence vote among them that will decide her fate.
Meanwhile, leading Brexiteer Jacob Rees-Mogg told the BBC that "I accept the confidence vote result but Theresa May should still meet the Queen and resign". Her situation remains perilous. If she loses then she can not stand in the leadership contest, and she will be replaced as head of the party and prime minister. In any normal situation, the Prime Minister's position would be untenable.
The gathering of the Conservative parliamentary party dissolved into cheering and raucous applause just after 9pm when the result was announced by Graham Brady, chairman of the Conservative body representing its Parliamentary members, the 1922 Committee. The expectation right now is that at some point she will have to change tack on Brexit.
The Prime Minister cleared the decks to lobby Tory MPs for their backing, cancelling a planned meeting of Cabinet and a trip to Dublin for talks with Irish premier Leo Varadkar.
"If we do support the Prime Minister we can honour the mandate that the British people have given us". "After the apocalypse, all that will be left will be ants and Tory MPs complaining about Europe and their leader".
Those who were pushing to force her out on Wednesday simply won't give up.