Speaking on Radio 4’s Today Programme, Mrs May denied she was delaying the vote on 11 December while she attempted to shore up support.
She insisted: ‘We are in the middle of five days of debate in Parliament which will lead up to a vote on this issue.’
Mrs May, once again using phrases and stock answers she has used during numerous interviews on Brexit, refused to be drawn on the possibility of losing the vote.
There are now 104 Tories who have said they will vote against the deal after prominent backbencher Johnny Mercer said he could not support it.
But the Prime Minister simply stated: ‘We haven’t had the vote yet.’
Brexiteers have raged against the deal ever since it was first announced last month but Mrs May said it was up to others to come up with a ‘Plan B’.
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She insisted she had negotiated a ‘good deal’ that ‘delivers on the referendum’, but refused to be drawn on whether she had an alternative.
Mrs May said: ‘That question is not for me, that question is for those who say that they want to oppose this deal.’
The Democratic Unionist Party, which props up Mrs May’s administration, made clear it would support the Government in a confidence motion if the Brexit deal was rejected by MPs on December 11.
However, the party’s 10 MPs would not back the Prime Minister if her Brexit deal, including the controversial Northern Ireland backstop measure, survives.
Asked if the DUP was prepared to precipitate a general election, the party’s Brexit spokesman Sammy Wilson told Radio: ‘If it comes to the point where the Government makes, shows, a determination to implement the Withdrawal Agreement with its damaging terms at present, or some future version of it, which is still equally damaging, we will not be supporting the Government.’
Referring to the DUP’s agreement to prop up the Tories in the Commons, Mr Wilson added: ‘If they break the agreement which they have with us, then they don’t have our support.
‘If they renege on those promises now, or in the future, we always have that leverage.’
Mrs May said she ‘recognised’ the concerns over the backstop but said: ‘Any deal, any agreement, any arrangement that we came to with the European Union would involve a backstop.
‘So, people talk about, ‘let’s have a Norway, or let’s have a Canada’, everything involves a backstop.
‘Secondly, none of the other arrangements that people have put forward fully deliver on the referendum. This deal delivers on the referendum.’
Asked whether the MPs would be given a separate vote on the backstop, the Prime Minister said: ‘The backstop is an integral part of the Withdrawal Agreement, but the backstop would be integral part of any withdrawal agreement and of any deal that was negotiated with the European Union.’
The PM signalled that MPs would decide whether the UK went into a backstop or extended the transition period.
Mrs May said: ‘There will be a choice between, if we get to that point, a choice between going into the backstop and extending the transition period.’
A European Court of Justice ruling on the reversibility of Article 50 is set to take place the day before MPs vote on Mrs May’s Brexit deal.
But Mrs May said that, while there is ‘no unilateral right’ to pull out of the backstop, the UK would have a choice over whether or not to enter into it.
Asked if she would be happy for Parliament to adjudicate on whether to go into the backstop or extend the implementation period, the PM said: ‘I think people are concerned about the role of the UK in making these decisions.
‘And, the obvious, in terms of the UK, is for it to be Parliament that makes these decisions.’