Gordon Brown concluded an emotionally-charged speech at a 'No' rally by telling voters to "have confidence" and "stand up and be counted" at the polls.
On SNP promises about an independent Scotland, he said: "We've had no answers. They do not know what they are doing. They are leading us into a trap."
He pleaded with campaigners: "Have confidence and say to our friends, for reasons of solidarity, sharing, justice, pride in Scotland - the only answer for Scotland's sake and Scotland's future is vote No."
An impassioned Gordon Brown told supporters at a No rally that his concerns were not a fear of the unknown but instead "the risks of the known."
He described independence as an "economic trapdoor down which we go, from which we might never escape."
And he outlined the "real risks" of currency uncertainty, debt default, a lack of financial reserves, rising prices in the shops, rises in interest rates, threats to jobs dependent on trade with the UK - all of which, he said, were "unaddressed by the SNP."
Former prime minister Gordon Brown has accused the SNP of "perpetrating a lie" about protecting the NHS with independence.
The SNP has suggested the NHS is at at risk due to health policies in Westminster, but Mr Brown said the Scottish Parliament already has powers to protect the service.
Brown told a pro-Union event in Clydebank, "It is the SNP who are perpetrating a lie about what the NHS can and cannot do in Scotland."
The No campaign has seized on leaked documents that suggest the NHS in Scotland is facing a funding gap of up to £450 million and major changes will be needed.
Former prime minister Gordon Brown has addressed a Better Together campaign rally in Dundee:
Brown: "It's the fat cats who will benefit most from the SNP's tax policies, not the ordinary people of Scotland." http://t.co/6C00YZbCMf
Gordon Brown in Dundee: "Our UK welfare state offers better protection for pensioners, disabled and the unemployed." http://t.co/AYzvqu9EBH
Gordon Brown called on the international community to turn their offer of help to return over 200 schoolgirls kidnapped by Boko Haram 10 weeks ago into "practical measures".
The former PM said Nigerian authorities needed support with night-vision equipment, air cover and suggested some of the girls could be in neighbouring Niger, Cameroon or Chad.
Gordon Brown called on Boko Haram to photograph pictures of all the schoolgirls they kidnapped four weeks ago to prove they are still alive.
The former Prime Minister tried to remain optimistic about the video which emerged yesterday showing approximately 100 of kidnapped schoolgirls as it meant "the majority of them are still alive", he told Good Morning Britain.
He also called "on every religious community to condemn Boko Haram and tell them that they cannot use girls in this way".
Former Prime Minister Gordon Brown has laid out the main reasons he believes Scotland would be better off staying in the United Kingdom.Read the full story ›
Pensions have a more secure future if the "risks are spread across the UK" than if Scotland choses to be an independent nation, according to Gordon Brown.
In a speech given later today the former Prime Minister will say:
The SNP Government has said the case for independence should be judged on whether Scotland would benefit financially or not.
It is clear that pensioners are better protected when the risks are spread across the UK and it is also clear that, in the year the SNP want independence, the Scots pension bill alone is three times the income from oil revenues.
Indeed the best deal for poorer pensioners is the redistribution of resources we have negotiated within the UK which allowed pensioner poverty in Scotland to fall under Labour, from 33% in 1997 to 11% when we left office.
Scotland faces a "pensions time bomb" if it choses to leave the union in September's referendum, according to former prime minister Gordon Brown.
Pensions will be more secure and cheaper to administer if Scotland remains in the UK, the Scottish Labour MP will say in his first speech for the cross-party Better Together campaign.
However, if Scotland leaves the union, the first annual pension bill would be "three times the income from oil", the former Labour party leader is expected to say in his speech.
And it faces a "pensioner time bomb" as the number of elderly people is growing faster than the working age population, an internal Department of Work and Pensions memo procured by Mr Brown said.
An independent Scotland's first annual pension bill will be three times as much as oil revenues, according to former Prime Minister Gordon Brown.
Mr Brown is expected to say that pensions would be more secure and cheaper to run if Scotland remains part of the United Kingdom, in a speech tomorrow for the anti-independence Better Together campaign.
Scotland faces a £100 billion public sector pensions bill and a "pensioner time bomb" as the number of elderly people grows faster than the working age population, Mr Brown will say.