The remarks come amid a febrile atmosphere at Westminster over Mrs May's leadership, with dozens of her MPs said to be plotting her downfall due to their opposition to her Chequers plan for Brexit.
Baker said in the interview that the party may suffer a "catastrophic split" if May sticks with the Chequers deal, which the cabinet supported in July. While some Brexiteers are unhappy with her premiership, they see May as their best immediate hope of ensuring the United Kingdom leaves the EU.
We will then have to pass our final agreed deal to the EU by 29 March, and 11pm that night we will have officially left the union.
He told Newsnight: "If you listen carefully to what Michel Barnier said there was no movement, there was an expression of confidence that we can get an agreement on the withdrawal agreement where we are going to give them £39 billion".
May's spokesman said her so-called Chequers proposal is the only serious, credible and negotiable plan available.
Divisions in the Conservative Party over Britain's relationship with the European Union contributed to the fall of all three previous Conservative premiers - David Cameron, John Major and Margaret Thatcher.
"I'm sorry, but this is the political end of Boris Johnson".
The trade union movement is preparing to throw its weight behind a public vote on the final Brexit deal because of fears the United Kingdom is going to "crash out" of the EU.
Speaking at a conference in Slovenia on Monday afternoon, Barnier said that a Brexit deal could be between six and eight weeks, calling such an outcome both "realistic" and "possible".
He added: "The key point is the (European) Commission has to be prepared to come to that party and say, "yes, we are prepared to show some flexibility on this", so that there can be a UK-wide free trade deal".
London and Brussels say they want to get a divorce deal at the October 18 EU Council or at the latest by the end of the year.
Once a deal is reached, it has to go to the United Kingdom parliament and the European Parliament for approval.
A hard deadline has been set of "late November" for the Chequers agreement to finalise the deal.
Without a deal, the United Kingdom would move from seamless trade with the rest of the European Union to customs arrangements set by the World Trade Organization for external states with no preferential deals.
Garvin said the jobs of only "hundreds" of JPMorgan's 16,000 staff in the United Kingdom would be immediately affected by Brexit, though that could rise to around 4,000 in the years to come depending on the settlement reached between Britain and the EU.
Supporters of Brexit acknowledge there may be some short-term pain for the UK's $2.9 trillion economy but say it will prosper in the long term when cut free from the EU which they cast as a failing German-dominated experiment in European integration.