He added:
Now, in an open letter to the country, Mrs May insists her deal honours the result of the referendum and says she will be "campaigning with my heart and soul" to win the Commons vote next month.
But sources said several senior ministers were talking up one "Plan B" idea of a Norway-style relationship with Brussels, under which the UK would have a more certain "exit mechanism" from the EU's rules but would be unable to end the free movement of workers from the Continent.
Under the Norway option, the UK would remain a member of the European Economic Area (EEA), without full EU membership.
A Government document leaked to The Telegraph reveals that economic modelling by the Treasury designed to allow MPs to compare Mrs May's deal to a no-deal exit would also include an "EEA-like scenario" – in a further sign that the arrangement is being considered seriously in Whitehall.
The leaked document states that the proposed Treasury modelling is designed to "support any 'meaningful vote' in Parliament on the final deal".
Tory MPs fear a series of exaggerated claims about the impact of an exit without a deal. In Belfast, a senior insider in the Democratic Unionist Party, which has threatened to pull its support for Mrs May's administration if she presses ahead with her deal, said the party had also held discussions with Cabinet ministers about "a Plan B".
Philip Hammond, the Chancellor, is said to be among ministers who have discussed the Norway idea in recent weeks – although an ally insisted he was squarely behind Mrs May's plan.
Separately, senior EU figures are war-gaming a scenario under which Brussels could agree to extend Article 50, the mechanism under which the UK will leave the bloc next March.
Diplomats believe that a reprieve could allow time for various possible outcomes, such as a new prime minister, a general election, a negotiation over a Norway-style Brexit, or a second referendum.
- The Telegraph