Setting out his Brexit plan, Mr Johnson said resolving the Irish border issue should be postponed so it forms part of the talks on a future trade deal and the United Kingdom should withhold a "substantial chunk" of the £39 billion divorce bill until that deal is done.
"It does not give the British people or our businesses the clarity and the certainty they need about our future trading relationship with the European Union in five or 10 years' time".
He said her Brexit deal could get through the Commons if it was stripped of the backstop measure - an insurance policy to prevent a hard border with Ireland - insisting that would be "relatively simple" to achieve.
A number of cabinet ministers quit on November 15 over fears the deal will keep United Kingdom tied the EU.
Mr Johnson blasted failures in Mrs May's government, speaking on the BBC's Andrew Marr Show, slamming her Brexit plan for leaving the United Kingdom "a diabolical negotiating position" and giving the European Union the chance to "blackmail" Britain.
"The outcome of that is that she'll have to come back to parliament again and hopefully this time with a deal we will accept".
They have discussed holding another vote - less than three years after the historic referendum - if Theresa May's deal is rejected by the Commons on Tuesday night.
Asked to give an "absolute, categorical promise" that he would not stand against the Prime Minister, Mr Johnson told the BBC's Andrew Marr Show: "I will give you an absolute, categorical promise that I will continue to advocate what I think is the most sensible plan".More news: Apple Watch update enables ECG functionality
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She said: 'If it doesn't get through, anything could happen - People's Vote, Norway-plus, any of these options could come forward and none of them are as good as the current arrangement we have got with the Withdrawal Agreement to vote on on Tuesday'.
And the second would be a leave, remain contest with a second question asking them if they prefer the existing deal or a no-deal departure on World Trade Organisation terms.
Senior Conservatives believe the Government will lose the crucial Commons vote on Tuesday and have told the PM to postpone the vote to avoid humiliation. "What I am suggesting is that there is probably more flexibility than is being suggested and actually we should have taken a robust line back then and we certainly should be taking one now".
"We voted to leave, we should deliver on leaving and we can do it in a way that works", she said.
Eurosceptic former party leader Iain Duncan Smith cautioned against the PM and her Cabinet deciding to "brazen it out", saying such an approach would be a "disaster".
"If we go into government straight away we would start negotiating straight away.
This is not a choice the government has so far been willing to make", the report said.