She suggested MPs could be "given a role" in deciding whether to activate the backstop, which is created to stop the return of a physical border.
Back in 2014, on the Notes From North Britain site, Tomkins indeed had plenty to say on Scotland and the EU.
Asked if Mrs May still felt she could command a majority in the Commons for the crunch vote next Tuesday, a Downing Street source said: "Everybody knows the parliamentary arithmetic".
"(It) would mean an immediate and probably indefinite loss of some security capability which, despite our best efforts, would likely cause some operational disruption when we leave", he said.
May also took aim at those in Parliament that she said were trying to "frustrate Brexit".
She said she understood there were concerns from MPs in Parliament over the backstop, a failsafe that would prevent a hard border between Northern Ireland and the Republic of Ireland.
Mrs May told BBC Radio 4's Today programme: "There will be a choice between, if we get to that point, a choice between going into the backstop and extending the transition period".
The Prime Minister has been advised by members of her Cabinet to delay asking MPs to deliver their judgment on her deal amid fears a crushing defeat could sink her Government.
"This risk must be weighed against the political and economic imperative on both sides to reach an agreement that constitutes a politically stable and permanent basis for their future relationship".
European Union negotiator Michel Barnier said on Thursday the deal was the best Britain will get, while British finance minister Philip Hammond said it was "simply a delusion" to think the agreement could be renegotiated if parliament rejects it.
Benn has attempted to amend May's withdrawal plans so that no-deal is ruled out, while Grieve has won backing for MPs to effectively direct the government's Brexit deal should the first draft be defeated.
This was echoed by Mr Hammond who has told MPs it is "simply a delusion" to think a better Brexit deal can be renegotiated at the 11th hour after warning a no-deal is "too bad to contemplate".
RICHARD Benyon was one of 26 Conservative MPs who rebelled against his own Government yesterday on a key vote which could determine what post-Brexit Britain looks like. We need to be honest with ourselves, the alternatives to this deal are no deal or no Brexit'.
Mr Javid continued: "They would have fewer options for pursuing criminals across borders, as we would lose our efforts through Europol and Eurojust, and it would take longer to track, arrest and bring to justice those who commit crimes internationally".
He wrote: "In the case of no deal, the European parliament and I have been clear that we want the citizens' rights deal that has been provisionally agreed to be ring-fenced and the EU must honour this".
Shadow chancellor John McDonnell said Labour "would not countenance" a no-deal Brexit but still opposes Mrs May's deal.
The policy will also make it harder for non-EU family members to join their loved ones in the United Kingdom, with the deadline being brought forward to 29 March 2022.