Theresa May has been rebuked after notes laying out a plot to push her soft Brexit through Parliament, by using pressure from foreign leaders and big business, were revealed.

Pro-Brexit MPs and even Cabinet sources warned the Prime Minister not to exaggerate the benefits of her deal or the risks associated with alternatives, after details leaked of a three-week, nation-wide blitz to begin the moment the Cabinet signs up to her plan.

It is believed the notes were drawn up by a Whitehall official and passed to MPs this week before they were leaked to the BBC and others.

The document claims Mrs May could be in a position to tell the CBI annual conference on November 19 that “we have delivered on the referendum.”

It claims Mrs May will seek the public endorsement of Japanese prime minister Shinzo Abe, Irish Taoiseach Leo Varadkar, Confederation of British Industry (CBI) head Carolyn Fairbairn, and Andy Burnham, the Labour mayor of Manchester.

“Government lining up 25 top business voices including Carolyn Fairburn and lots of world leaders eg Japanese PM to tweet support for the deal,” it says.

In the following days, the note says, May will visit different parts of the country and loyal ministers will do a media blitz to try and persuade the nation a good deal has been struck.

It adds: “Other business leaders to come out and back it eg Adam Marshall from Chambers of Commerce and supportive voices in devolved regions like Andy Street and Andy Burnham. Also hoping to get 3rd Sector voices out supporting it.”

UKIP blasted the leak as a ‘Brexit betrayal’ on social media, adding: “This leak chimes with leaks we’ve got from within the European Parliament.

“Theresa May and her Tories will forever be known as the party that sold out Brexit, and the so-called Tory Brexiteers, Boris Johnson, Jacob Rees-Mogg and others will not escape blame.”

No 10 sought to distance itself from the document, with a government spokesman telling The Times:

“The misspelling and childish language in this document should be enough to make clear it doesn’t represent the government’s thinking. You would expect the government to have plans for all situations — to be clear, this isn’t one of them.”

However, a Brexiteer cabinet source hit back, blasting: “Despite the denials from No 10, this has all the hallmarks of Robbie Gibb [Mrs May’s director of communications].

“It’s highly presumptuous of them to assume that the people listed will go out and back the deal.

“If they’d put as much effort into the negotiation as they seem they do dipping everyone’s hands in blood we may have reached an agreement that cabinet ministers could go out and back.”