David Cameron and George Osborne have issued an impassioned appeal for a vote for Remain, warning that leaving the EU would be the "big mistake" putting Britain's prosperity at risk.
With campaigning in the referendum set to resume after the shocking murder on Thursday of Labour MP Jo Cox, Mr Osborne said he hoped the debate could be conducted in a "less divisive tone" in the final days before polling.
Writing in The Mail on Sunday, he said: "Let's have less inflammatory rhetoric and baseless assertion, and more facts and reasoned argument."
But while the British Chancellor said it was "deeply troubling" that the Leave camp continued to ignore the warnings of independent experts like the IMF about the threat to the economy, pro-Brexit Justice Secretary Michael Gove insisted Britain would thrive outside the EU.
His comments were in sharp contrast to Mr Cameron who, in an article for the Sunday Telegraph, warned that the country was facing an "an existential choice" from which there would be "no turning back".
He said the economy "hangs in the balance", with trade and investment set to suffer, in the event of a vote for Leave, a "probable recession" that would leave Britain "permanently poorer".
"If you're not sure, don't take the risk of leaving. If you don't know, don't go. If we were to leave and it quickly turned out to be a big mistake, there wouldn't be a way of changing our minds and having another go. This is it."
In an interview with the Sunday Times he criticised Mr Gove and Boris Johnson for urging voters to discount the advice of economic experts.
"If you were about to get into your family car and drive your family at high speed on a motorway and the mechanic said to you, 'The brakes are faulty, the fuel is leaking, don't get in that car', you would listen to that expert," he said.
"Would you take a risk with your family and get into a faulty car? You wouldn't."
His warning was echoed by Mr Osborne who pointed to the latest assessment of the IMF that 440,000 jobs could be lost if Britain made "the most terrible mistake" of withdrawing from the EU.
"I say to people weighing up how to vote on Thursday. Stop and think. If there's any doubt in your mind, don't take the risk with an irreversible vote to Leave," he wrote.
While Mr Gove acknowledged there were risks in leaving the EU, he insisted he did not believe a vote for Out on Thursday would plunge the country into recession.
"There are great things that Britain can do in the future as a progressive beacon. By voting Leave, we have that opportunity. People should vote for democracy and Britain should vote for hope," he told the Sunday Telegraph.
"There are economic risks if we leave, economic risks if we remain. I don't think there will be a recession as a result of a vote to Leave."
With the latest clutch of opinion polls suggesting the Remain camp is regaining ground after slipping behind Leave, Mr Gove said the result was too close to call.
"Many of the arguments we have made have resonated. I don't know because I think the result is on a knife edge. I genuinely think that the public are making up their mind at the moment. It could go either way," he said.
In the first poll conducted entirely following the murder of Mrs Cox, Survation for The Mail on Sunday put Remain back in the lead on 45%, three points ahead of Leave on 42%.
Despite deep anger among many pro-Brexit MPs at the way Mr Cameron had led the Remain campaign, Mr Gove insisted he would carry on as Prime Minister whatever the outcome of the vote.
"I don't want to have anyone else as Prime Minister other than David Cameron and if people spend their time thinking about some of this stuff then they are getting in the way of two things: one, a fair, open, fact-based referendum debate, and two, the Conservative Government continuing afterwards in a stable and secure fashion," he said.
Boris Johnson also backed Mr Cameron staying on as Prime Minister, saying the Tory party leader had his "full confidence".
In an interview in The Sun on Sunday, he said: "The most important thing first of all is that David Cameron should stay on as Prime Minister - and I am sure he will.
"He will need to send a very powerful message to our European friends and partners that this is not a vote against Europe. It will be a vote against the institutions of the European Union."
He told the newspaper that, in the event of Brexit, steps could happen within days, including quitting the jurisdiction of the European Court of Justice.
Calling the referendum a "once-in-a-lifetime chance" to take back control of the country's democracy, he said: "We are working flat out to achieve this. It's a chance to take back control of huge sums of money and to take back control of our trade policy."
Defending the Leave campaign's focus on immigration, Mr Johnson said he was "pro-immigration" but wanted a policy that was "fair and balanced".