British Prime Minister Theresa May on Sunday warned that a failure to deliver Brexit would be "a catastrophic and unforgivable breach of trust in our democracy".
Writing in the Sunday Express newspaper, May pleaded with lawmakers to back her Brexit deal in Tuesday's vote, the BBC reported.
Not doing so risks the UK leaving the European Union (EU) with no deal or Brexit not happening at all, she said.
May said the House of Commons vote on her Brexit withdrawal deal would be the "biggest and most important decision that any MP of our generation will be asked to make".
The Prime Minister is widely expected to lose the vote on the withdrawal agreement she reached with the EU, which some ministers have said will lead to Brexit "paralysis".
May said: "When you turned out to vote in the referendum, you did so because you wanted your voice to be heard.
"Some of you put your trust in the political process for the first time in decades. We cannot - and must not - let you down.
"Doing so would be a catastrophic and unforgivable breach of trust in our democracy.
"So my message to Parliament this weekend is simple: It is time to forget the games and do what is right for our country," May said.
The UK is due to leave the EU on March 29 automatically, whether the deal is passed by British lawmakers or not.
On Monday, the debate on the vote on May's deal will resume for a fourth day.
The vote had been scheduled to take place in December but was called off at the last minute by the Prime Minister, who was facing almost certain defeat.
Last week the government was defeated twice in the House of Commons on Brexit votes.
In the first, lawmakers backed an amendment aimed at making it more difficult to leave the EU without a deal.
While in the second they voted for the government to come back to the House of Commons with a plan B for Brexit within three days should it lose Tuesday's vote.