Prime Minister Gordon Brown has billed Labour as "the front line of defence" against the SNP.
And he declared that Scottish Labour leader Wendy Alexander would be the next first minister of Scotland.
Mr Brown was addressing the Scottish Labour conference in Aviemore, the first since the party lost power to the SNP in Scotland last May.
He also used his speech to reinforce a unified Britain in making the world a better place.
Speaking from the stage without notes, the prime minister claimed the Scottish Government had put youngsters' future at risk through cuts in education spending.
He declared: "I say we should stand up for the people of Scotland and for the young children of Scotland and we will be the front line of defence for them against those SNP cuts.
"Those cuts are not only wrong, they are depriving our country of its best future."
Listing various SNP policy decisions in areas such as educational maintenance allowances, Mr Brown declared: "We will be the front line of defence for young people that need that help to get the qualifications.
"And we will stand up against the SNP not only because their policy is wrong but they are depriving people of the best chance of a future for Scotland in this new global economy."
Mr Brown also paid tribute to Ms Alexander and her warning that Labour had to learn the lessons from its defeat in the Holyrood election.
He went on: "And I believe that Wendy Alexander is not only the leader of our party here in Scotland but she will be the next first minister of Scotland whenever an election is declared."
The prime minister went on to say that the current generation could be the first to eradicate centuries-old diseases and ensure every child in the world had access to education, if the UK worked with other countries.
The prime minister also stressed opportunity in his speech
Mr Brown said the SNP's "separatist policies" would not prepare Britain for the future.
The Nationalists, he claimed, wanted to "build barriers and erect borders", while the prime minister threw his support behind the new, independent Constitutional Commission, set up to review Scottish devolution 10 years on.
Mr Brown spoke of the achievements of Labour in more than a decade in power at Westminster, telling delegates it had created 200,000 jobs across Britain and brought in the national minimum wage.
He outlined his desire for a country where there was opportunity for all - announcing an extra £120m to help athletes win medals at the Olympics and the Commonwealth Games - to be held in Glasgow in 2014.
The Kirkcaldy and Cowdenbeath MP told delegates he was proud to have gone to his local school in Fife and said he was angered by children destined to fail through poverty, or youngsters unable to stay on at school because of parental circumstances.
"I believe in a Scotland where everyone should have the chance to rise as far as their talents can take them, where the talents of each of us should contribute to the wellbeing of all," he said, outlining his aspiration to "unlock all the talent of all the people".
Mr Brown stressed the rise of India and China - places where it was no longer about the race out of low pay, but the one to better skills, adding: "While those countries produced five million graduates, this country produced just 400,000.
"We used to talk about the arms race. Now we have a skills race around the world.
"That is why the message that we have always believed in - that social justice is about everybody having the opportunity to make the most of their lives - is the message for the future of our economy as well."