The UK's exit in March was "in danger" if MPs did not vote for it, she added.
It comes as the United Kingdom parliament debates May's deal on Wednesday, before the meaningful vote scheduled for Tuesday, January 15.
Meanwhile, writing in Daily Telegraph, ex-Foreign Secretary Boris Johnson said the option of leaving the European Union with no deal was "closest to what people actually voted for" in the 2016 European Union referendum.
The prime minister was forced to abandon plans to hold a vote on the deal in December after more than a hundred Conservative MPs and the Democratic Unionist Party, which props up May's minority government, vowed to vote against it.
Wall Street Journal editor-at-large Gerry Baker says British PM Theresa May survived her party's no-confidence vote because there is no time to elect a new leader before the January 21 deadline for the Brexit deal to be finalized.
The prime minister tells the Andrew Marr show that Britain is heading for "uncharted territory".
Congestion at the ports caused by customs checks being reintroduced on goods has been cited as among the likely negative effects of a no-deal withdrawal.
On Sunday, Ms. May reiterated her opposition to holding a second referendum, saying it would be divisive and disrespectful to those who voted to leave in the initial vote, and also highlighted a lack of time available to hold a new referendum.
Assets worth almost 800 billion pounds ($1 trillion) are being moved from Britain to new financial hubs in the European Union ahead of Brexit, consultancy EY said on Monday.
Lawmakers are due to vote on whether to accept May's exit deal in the week beginning 14 January.
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For girls, greater daily hours of social media use corresponded to a stepwise increase in depressive symptoms. They also completed the Moods and Feelings Questionnaire which is used to screen for symptoms of depression .
El-Sissi says Egypt, Israel co-operate against militants
In February, Egypt launched "Comprehensive Operation Sinai 2018" in an effort to rid the peninsula of terrorists. Israel and Egypt share a number of regional interests - including the containment of Iran and combating ISIS.
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What's more interesting here is how Apple will be able to boost its services devision down the line with this announcement. Owners of these televisions will be able to access their existing iTunes movie and TV show library from within this app.
Congestion at the Channel ports caused by the reintroduction of customs checks on goods has been one of the most commonly cited negative effects of a no-deal withdrawal from the European Union at the end of March. "We have got a week".
Emily Thornberry said her party would be happy to "go back to the people" if it won power at a snap general election but failed to get its own Brexit plans through.
"The EU has shown in the past that it will move but only if faced with a resolute red line on the part of the United Kingdom government", deputy DUP leader Nigel Dodds said in a statement.
"The coming days will show if this government is made of the right stuff", he added.
Shadow worldwide trade secretary Barry Gardiner suggested Labour could offer a referendum on a renegotiated Brexit deal.
Prominent Brexiteer Peter Bone said a no-deal scenario was the only way to guarantee the United Kingdom actually leaves the EU.
Asked if he could guarantee that no one would die as a result of a no-deal Brexit, Mr Hancock told Sky News' Sophy Ridge On Sunday: "I'm confident that we will have the unhindered supply of medicines so long as the plans that we have in place are properly enacted".
"But the fact is we're need a compromise to take this forward in a way that works for the bulk of the country and I think that's a genuine attempt by the Prime Minister to do that".