The extent of opposition to her plans could be laid bare on Wednesday when pro-Brexit lawmakers, including the Northern Irish party that props up her minority government, plan to stage a rebellion on a piece of legislation related to the province.
In its report, the National Audit Office said that political uncertainty and delays in negotiations with the European Union have hampered preparations for new border arrangements, and the government is now racing to bolster computer systems, increase staffing and build new infrastructure to track goods.
He said it was not in the national interest to back a bad deal.
A cross-party group of MPs are plotting to thwart Brexit by tabling a "killer" amendment to demand a second referendum.
Brexit negotiations must be tied up by the end of next month to allow new laws to be put in place in time for exit day, Dominic Raab has said.
David Shiels, a policy analyst with thinktank Open Europe, noted that neither the EU or the Irish government "would believe that a longer-term customs union would be politically sustainable from a United Kingdom point of view". But if she had to concede an extension, it would only be for a few months as it would still end "well before the end of this Parliament".
May said it was "incumbent on all of us in public life to be careful about the language we use".
The graphic nature of the media attacks appeared to unsettle even some of May's biggest critics.
But almost every MP's disapproval of the quotes was followed by condemnation of May's handling of the negotiations.
The UK Prime Minister has previously said that one idea is to extend the UK's transition period beyond 2020, but she said this was "undesirable" and would have to end "well before" May 2022.
People think Meghan Markle broke a cultural tradition and they're NOT happy
This is just the latest way the Duchess of Sussex has honored the Queen . PA Wire/PA Images The duke and duchess at their hotel in Fiji.
A failure of the party to unite would bring in its wake an election and high risk of an ultra-left populist Labour government, the newspaper stated.
Number 10 said: "This is nothing more than a partial reflection of advice to ministers, and not of decisions taken".
During her meeting with the gathering of British and Irish parliamentarians, Mrs Bradley was also challenged on the potential of violence if Brexit saw physical infrastructure return to the border.
The gulf in the positions defended by May on Monday and Brussels is wide.
But those in favour of Brexit are concerned that a longer transition period would further delay the moment of the UK's proper departure from the European Union, and could cost billions in terms of extra payments.
Brussels further wants to keep Northern Ireland aligned with European Union customs rules and regulations for the duration of continued talks on a permanent solution.
While she was ready to explore "every possible option" to break the impasse, she said a "critical" first step should be a legally-binding agreement on a temporary UK-EU joint customs territory to avoid the need for a Northern Ireland-only backstop.
The stakes for May are rising quickly at home.
May's Northern Irish allies, the Democratic Unionist Party, have raised the stakes by threatening to vote against next week's budget if the deal results in any special status for the province.
Tánaiste Simon Coveney said there was a "misunderstanding" among some in London on how the so-called "backstop" for Northern Ireland was arrived at.