Prime Minister David Cameron has said that UK faces an "existential choice" in the EU referendum from which there would be "no turning back", BBC reports.
Cameron said choosing to leave the EU in Thursday's vote would be a "big mistake" and lead to "debilitating uncertainty" for up to a decade.
However Michael Gove told the Sunday Telegraph the UK could become a "progressive beacon" by leaving the EU.
The Leave campaigner urged people to "vote for democracy".
Cameron said the EU vote was the "ultimate democracy" and represented what Labour MP Jo Cox, who was killed on Thursday in her West Yorkshire constituency, had stood for.
Writing in the Sunday telegraph, Cameron, who is campaigning for Remain, said Cox had "embodied Britain at her best - a country that is decent and compassionate".
The "irreversible" referendum was a "watershed moment" for the UK and a question "about the kind of country we want to be", he said.