Video report by ITV News Political Editor Robert Peston
Boris Johnson says workers rights will be enshrined in the Brexit deal he's trying to get MPs to back.
Mr Johnson insisted the agreement did not signal a "race to the bottom".
The prime minister told ITV News Political Editor Robert Peston that he would be able to reassure MPs worried about the potential erosion of employment rights in his new bill.
"We can do all things differently to a higher standard and our aspirations to high levels of protection will be enshrined in the Political Declaration," he said.
"The withdrawal agreement bill will, almost certainly, contain the kind of protections and provisions you are talking about."
He said a vote on his Brexit deal is a chance to repay the faith of the people who voted to leave the European Union.
Mr Johnson said once agreed, the nation would "heave a great sigh of relief".
He said he had "ambitions" to go further than the EU in certain areas - mentioning a possible ban on the export of live animals as an example - but they are "aspirations".
He said: "We want the highest protections, the highest standards in this country but I also want colleagues across all sides of this house to think about a world tomorrow night in which we've got this thing done, we've got it over the line.
"I think the nation will heave a great sigh of relief. That will be our moment to get on with the priorities of our country.
"The appetite to move on is strong in the UK but it's also strong with our friends and partners."
Mr Johnson's Brexit plan all comes down to the numbers - and whether he has enough support in the House to get it done on Saturday.
Those numbers have been dented by earlier action which saw the Conservative whip withdrawn on 21 rebel Tory MPs who voted against earlier efforts.
When asked whether anyone who defied him again would face the same action, he said: "I'm not going to talk about whipping arrangements... What we want to do is to get colleagues to vote for this great deal - it's a great deal for this country, it's a great deal for Europe, actually, for our relations with the EU.
"We can use this for where we want to go... we build a great big, deep and special partnership, based on a jumbo free trade arrangement."
The prime minister insisted the new deal to be debated was a "great deal for the whole of the UK".
"From the get-go, we take back control of money, borders, laws, all the rest of it, according to the democratic will of the people of this country," he said.
"So, in that sense, it busts out of the backstop... the problem with the previous deal which kept us locked in the customs union and the single market. So it's a vast, vast step forward."
Asked whether Saturday's vote was the biggest thing he has done professionally, the PM said: "Well I wouldn't deny that, I think it's a very big moment for our country."
Pressed on whether the vote could be seen as a confidence vote if he loses and whether he would call one he said: "I will not contemplate any such scenario.
"This is a very big moment for our country and also a big moment for our democracy and parliamentarians because I do think we have a choice... we have to consider how long we can delay and seem to frustrate what was a pretty clear expression of the democratic will of the people."
He said the last few weeks had not been a particularly fine moment for parliament or MPs.
But he said now was a "moment of great optimism, because this a chance to show that we believe in ourselves, that we trust our democracy, that we trust the people, they made a judgement, we're gonna respect it and get it done and then we're going to work with EU to build a new partnership."