In her speech in Belfast on Friday, May warned Brussels negotiators to "evolve" their position on Brexit or else a deal would not be reached. This is referred to as the "no deal" or "cliff-edge" scenario.
In a clear sign that plans are accelerating to cover the negotiations collapsing, the Prime Minister said the technical notices would tell firms and individuals what to do "in the event of a no-deal scenario".
"There is obviously an attempt to try and ramp-up the pressure".
"You can not say there will be no hard border and then propose a course of action that will deliver a hard border".
Its eight months to go before Britain is to leave the European Union on March 29 2019, May's government, parliament, the public, and businesses remain deeply divided over what form Brexit should take.
The EU has long complained that May has delayed the Brexit negotiations because internal bickering within her Conservative Party has brought her government to the brink of chaos.
In her speech May hit back, dismissing Johnson's suggestion that technology could allow customs checks without physical infrastructure, saying such systems did not yet exist.
Her new Brexit Secretary, Dominic Raab, vowed to "intensify" negotiations after travelling to Brussels for his first meeting with the EU's chief negotiator, Michel Barnier.
The European Commission is refusing to badge, allowing partial access to the Single Market; at the same time, Barnier expects the United Kingdom to honour the backstop agreement signed in December 2017, which the United Kingdom is gradually calling into question.
French European affairs minister Nathalie Loiseau said: "We will work on the basis of our principles and see to what extent our British partner fully gets it, including the British Parliament".
The UK government has taken the somewhat unprecedented step of translating the executive summary of its Brexit White Paper into 22 European languages.
The British government has also stepped up planning for a so-called "no deal" Brexit that could spook financial markets and dislocate trade flows across Europe and beyond.
Products may require new authorisations and certifications, while professionals may need to have their qualifications recognised by an EU27 state as well as the UK.
He added: "Politics is all about trust and once it is lost it is impossible to win back".
"The protection of the peace process and upholding our binding commitments in the Belfast Agreement are grave responsibilities", she said. "However, the outcome of negotiations can not be predicted".
'There needs to be a narrative to say, "Actually we don't want this to happen but we have to prepare just in case it does and here are all the things that we have to do",' he said.
Meanwhile, Mr Davis, whose resignation from Mrs May's top team was followed by that of former Foreign Secretary Boris Johnson, told the Sunday Express the government should "start again" on withdrawal plans.