The Labour leader made the admission as Transport Secretary Chris Grayling denied there was a "void" in government over Brexit during an interview with Sky News.
Ms Rudd said it was "right" for the government to make preparations for a no-deal Brexit, comparing it to wearing a seatbelt when driving a fast vehicle.
Mr Grayling also said: "I have not asked for military support for the operations in Kent - that will be handled by Highways England and Kent Police".
"A day is long time in politics so things can change but as it stands it is likely I will vote for the deal, yes", he said. "I am committed to getting the best outcome for this country, which is supporting the prime minister's deal".
"Under any scenario, people are going to be poorer, people are going to lose their jobs".
The Highlands MP added: "I would like the House of Commons now to take control because the Prime Minister has failed to give leadership".
If you feel like you ought to know more about Brexit.
Labour is also set to vote against the deal, but leader Jeremy Corbyn has resisted growing calls from within his own party to get behind another European Union referendum, insisting a general election is still his top priority if the deal is rejected.
Mr Blackford said that revoking Article 50, which sets a deadline of 29 March for the date of departure, and holding another referendum would be the most sensible option for moving forward.
"I think parliament is very committed to try to stop no-deal, but I think we have to recognise that there is a deal on the table, it does broadly deliver the Brexit people voted for, and if we don't find a way to get this through, we are taking some very big risks".
Bus driver rescues wandering youngster
A passenger can be seen getting up and giving her coat to Ivic for the little boy, who quickly fell asleep in his rescuer's arms. The boy Ivic rescued "is the ninth lost or missing child found by MCTS Drivers in recent years", the release states.
"It will open the door to extremist populist political forces in this country of the kind we see in other countries in Europe", Grayling told the newspaper.
"We will do everything we can to prevent a no deal exit".
Former minister Jim Fitzpatrick told the Commons on Friday that he was "not far away" from backing May's deal, saying the "danger of no deal is still there" and the PM's plan was "the only real alternative on the table".
Pressed on what happens if the deal is defeated, Mr Barclay said he suspected the Commons would support something "along the lines of this deal" but declined to speculate on whether the government had a Brexit "plan B" lined up.
MPs will gather at Westminster Monday to resume their marathon debate on the Brexit bill ahead of the vote early Tuesday evening.
But officials said Brussels would be in listening mode, and take guidance from the prime minister as to the next steps should she suffer a heavy defeat as is widely expected.
Transport Secretary Chris Grayling told the Daily Mail that the party risked cheating and isolating the millions of United Kingdom citizens who voted to leave the European Union, ending its 350-year period of "moderate" politics.
In the event May's deal is rejected on Tuesday, her government will have just three days to bring a revised plan back to parliament. However, with more than 100 Tory MPs opposing the deal, it is expected to be rejected.
Meanwhile, Mr Corbyn repeatedly refused to guarantee Labour would campaign to deliver Brexit at a snap general election.