In a statement from the House of Commons, the prime minister responded to her party's critics by insisting that any power to extend the United Kingdom's transition outside the EU would only be used as a last resort.
It also intensified its attack on activists for a new referendum on the EU, accusing them of demanding a "political vote" to nullify the will of the people expressed in the 2016 decision to leave the bloc.
"Serving our national interest will require that we remain calm during these last stages of negotiations, the most difficult part of all," the Prime Minister told parliamentarians.
"It will mean not giving in to those who want to stop Brexit with the vote of politicians: politicians tell people they were wrong the first time and should try again."
"And it will mean focusing on the prize that we have before us: the great opportunities we can open for our country when we overcome these final obstacles in the negotiations."
Ms. May's statement on the EU summit last week in Brussels followed the anger among the Eurosceptic Tories in their latest attempt at engagement with Brussels in the search for a Brexit breakthrough.
At the meeting of EU leaders, the Prime Minister held talks on the possible extension of the "implementation period" after Brexit, when the United Kingdom will remain closely linked to the bloc beyond the current final date of December 2020.
In defense of the measure, she told the parliamentarians that the proposal was an "insurance policy".
"If by the end of 2020 our future relationship was not ready, the proposal is for the UK to make a sovereign choice between customs support across the UK or a short extension of the implementation period," he said.
She added: "I have not committed to extend the implementation period.
"I do not want to extend the implementation period, and I do not think it's necessary to extend it," he said.
Ms. May told parliamentarians that according to her plans, Britain will completely cut off relations at the time of the next general election in 2022.
He also insisted that the "95 percent" of the expected withdrawal agreement that was being negotiated between the United Kingdom and the EU was completed by the dispute over the Irish border with "the only point left".
"There are some limited circumstances in which it could be argued that an extension of the implementation period might be preferable if we were sure it was only for a short time," he said.
"A short extension of the implementation period would only mean a set of changes for the companies at the moment in which we move towards the future relationship.
"But in any situation like that, we would have to be out of this implementation period long before the end of this parliament."
Tory Backbenchers expressed his anger over his plans in the commons today.
Brexit News: Theresa May is under fire from the Brexiteer hard-line backbenchers
Former cabinet minister John Redwood said a longer transition period could add up to £ 20 billion to the Brexit divorce rate funded by UK taxpayers.
He told the Prime Minister: "The economy has deliberately slowed down due to a fiscal and monetary contraction that we must eliminate.
"We need tax cuts to increase people's wages so they have more spending power.
"All this is possible if we do not donate £ 39 billion to the EU, and all this would be even more possible if we did not promise another £ 15 billion or £ 20 billion for some time, never if we are going to give it one more time now.
"Then, when will this government face the EU, when will it say it wants a free trade agreement and do not see the need to pay it, and when will it exclude the signing of a withdrawal agreement, which is a surrender?" document that we can not afford? "
John Whittingdale, another former cabinet minister, asked if the Prime Minister appreciated "the frustration felt by many of my constituents and others that more than two years ago since the referendum and that we agreed that we will not regain control of our laws, borders and money. for more than four years after the referendum. "
She added: "Does she understand that for many of them and for us it is too long?"
Ms. May's call to arms followed a series of brutal criticisms by unnamed Tory parliamentarians demanding the end of her prime minister's position over the weekend.
An unnamed deputy suggested that she should "take her own bow" to a backbenchers meeting while another said, "The time is coming when the knife gets hot, gets stuck in the front and writhes, she will die soon."
Brexit News: Theresa May updated Commons in the Brexit talks today
Parliamentarians from both sides of the Commons came together to condemn the aggressive language used by the enemies of the Prime Minister.
The former Brexit minister, Steve Baker, said those responsible for the brutal comments "have dishonored completely."
He said: "I hope they are discovered and I hope that she will remove the whip from them."
Yvette Cooper, working president of the Internal Affairs Commission, criticized the abuse as "violent, dehumanizing and frankly misogynistic language."
Former Home Secretary Amber Rudd hoped there would be "no language like that in the future."
Mrs. May told parliamentarians: "I think it is an obligation for all of us in public life to be careful with the language we use, there are passionate beliefs and passionate views on this subject and other issues, but whatever the subject, we must all be careful with our language. "
Earlier, the prime minister's spokesman said: "I do not intend to dignify those specific anonymous comments with an answer.
"The Prime Minister has always been very clear that we must set a tone in the public discourse that is neither dehumanizing nor derogatory.
"Personal vitriol has no place in our politics."
Brexit News: John Redwood has demanded that Theresa May be stopped. before Brussels
In the exchanges that followed his statement, Labor leader Jeremy Corbyn condemned the government's handling of Brexit as "a complete disaster".
He said: "The Conservative Party has spent the last two years arguing with itself instead of negotiating a reasonable agreement in the interest of the public.
"Even at this crucial point, they are still fighting among themselves.
"This government is incompetent in the extreme, paralyzed by its own divisions."
Ms. May accused Mr. Corbyn of "putting politics above the national interest."
She said: "Throughout all this, all we have seen from the Labor Party, from him, is to play politics with this problem.
"One minute they want to accept the referendum, the next they want a second referendum, one minute they want to say that free circulation will end, the next they say that free movement is still on the table."
"He's doing everything he can to thwart Brexit and trigger a general election."