Home Secretary John Reid has become the latest Labour heavyweight to attack Nationalists at the Scottish Labour Conference in Oban.
John Reid said the SNP were not fit for purpose
Dr Reid, MP for Airdrie and Shotts, said the SNP were unfit to face the great challenges of the coming decades.
He said international terrorism, organised crime, mass migration and the environment did not stop at the border.
SNP leader Alex Salmond claimed Labour was "scared stiff" of his party and acting in its own self-interest.
Dr Reid's comments came after similar attacks by Prime Minister Tony Blair and Chancellor Gordon Brown.
He dismissed the SNP and their cause as "not fit for purpose" in the modern world.
He told Labour delegates: "The true liberation of this country lies not in the rhetoric of the Nationalists but in developing the talents of each and every one of our children through education. That is the Scottish heritage."
Dr Reid added: "In the face of the environment, international crime and terrorism, and mass migration, the narrow Nationalists stand helpless.
"Because these challenges cannot be tackled by putting border guards at Gretna Green."
He also emphasised the "interdependence" of Scotland and England.
The home secretary said that almost one million Scots lived and worked south of the border.
"A million Scots working in England in every trade and every profession up to the prime minister - and I'm told the next prime minister might be Scottish as well," Dr Reid said.
The home secretary said that in 1707 when Scotland first entered the union only 30,000 Scots had English relatives.
He said: "Now there are over two million of us, who either have an English partner, as in my case, or have family in England, as in many other cases.
"For the first time in history almost half of all Scots have relatives from south of the border."
Dr Reid said separating the two countries would not be acceptable to these people.
The home secretary's attack followed an ICM survey for the Sunday Telegraph which suggested support for Scottish independence had reached 52% among Scots and 59% in England.
The SNP leader said Labour had a vested interested in keeping Scotland and England from being independent because it wanted to run England on Scottish votes.
Mr Salmond said: "They, like the Tories, also want to get their hands on Scottish resources.
"I mean what they're speaking from is not the national interest of Scotland or England. It's the self-interest of the Labour party and Labour party politicians like John Reid, Gordon Brown, who want to be prime minister".
Later Scottish Secretary Douglas Alexander joined the attack on the SNP.
He told delegates in Oban: "The Nationalists just don't get it.
"While children throughout Europe are learning Cantonese, they (the SNP) want to re-enact Culloden."
Acknowledging voter unease over Iraq he said: "If the question is the rights and wrongs of the action in Iraq, the answer is not Scottish independence.
"If the problem is stability in the Middle East, a border between Scotland and England is not the solution."