Urging voters to back the No vote today, the former prime minister told a Scottish audience: “What we have built together by sacrificing and sharing, let no narrow nationalism split asunder.”
In a passionate speech, Mr Brown said the SNP is leading Scotland into “a trap” - an “economic minefield where problems could implode at any time”.
The Labour MP told voters to remember “Scotland belongs to us all” in a call to be proud of what the country has achieved as part of the UK.
He also dismissed reports of concern among MPs in the UK regions about the new powers on offer to Scotland if it votes No, insisting “the rest of the UK I think will be quite happy with these changes”.
Mr Brown addressed hundreds of UK supporters at a community centre in Glasgow, standing shoulder to shoulder with his former Chancellor Alistair Darling, leader of the Better Together campaign, and Scottish leaders from Labour, the Conservatives and Liberal Democrats.
He said: “The nationalist vision has only one aim in mind, to break every single constitutional and political link with our friends and neighbours in the UK.
“The vote is not about whether we are a nation, we are, yesterday, today and tomorrow
“The vote is whether you want to break and sever every link.
“Let us tell the undecided, the waverers, just what we achieved together
“We fought two world wars together an there is not a cemetery in Europe that does not have Scots, English Welsh and Irish lying side by side.
“And when young men were injured in those wars they did not look to each other asking are you Scottish or English, they came to each other’s aid because we are part of a common cause.”
But at the same time Scottish First Minister Alex Salmond was setting out why he is confident voters would back independence when they go to the polls.
Speaking on a visit to an engineering firm in Stewarton, Ayrshire, the SNP leader said: “My confidence is based on what’s happening in the streets and communities around Scotland, I think there’s a very substantial movement towards yes because people understand this is a once in a lifetime opportunity to take the future of this country into our hands.
“When people go into the polling booths tomorrow they are going to vote for something, for a that vision of more prosperous but also a more just society, that’s what’s going to motivate people in the polling stations tomorrow.”
He added: “I think the movement is to Yes. I’m certain of that actually. I think we’re being helped enormously by two things. One is the total negativity of the No campaign, it’s a dismal, depressing no campaign. But also the positive message of Yes.
“We see in the employment figures today, a 45,000 increase in Scottish jobs, soaring beyond the UK level, Scottish unemployment well down, that’s fantastic news for Scotland.”
Mr Salmond said the Yes campaign was still the underdog in the referendum.
He said: “We’re in the hands of Scotland and there’s nowhere better to be, or safer to be, than in the hands of the people of Scotland. They will exercise their judgment.”
The First Minister said: “I think we are the underdogs and have been throughout the campaign. We’ve had the kitchen sink and quite a bit of the living room thrown at us by Downing Street and the London establishment. That makes us the underdogs.
“However as we know in life, in politics and certainly in this festival of democracy, underdogs have a habit of winning sometimes.”