Gordon Brown set out a series of international challenges to the Scottish Labour conference, contrasting them with the SNP plans "to erect new barriers within this island when old barriers are coming down".

Speaking on the opening day of the party's conference in Aviemore, the Prime Minister set out to persuade Scots that the nation is not diminished by being part of the United Kingdom, but that Scots in his cabinet are able to make a difference on the world stage by being part of a bigger country. He warned of the danger of taking for granted the advantages of the four parts of the UK sticking together.

Mr Brown was speaking without notes for the first time in a major conference speech, following an example set by his Tory rival David Cameron at Conservative conferences.

The Prime Minister's speech did not directly address Scottish Labour's loss of power at Holyrood last year, what went wrong or what is needed next to make sure Labour plans for a recovery at future elections.

Those issues are more likely to feature in the speech today by Labour's Holyrood leader, Wendy Alexander. She received generous praise from the Prime Minister, who forecast she will be the next First Minister.

However, facing the first party conference since Labour lost its 50-year dominance of Scottish politics, his under-lying intent was to rally the faithful with a reminder to delegates of the value on which they can agree and campaign. There were lengthy pas-sages about the government's achievements and aims in tackling African poverty, which have proved effective in recent years in cementing Labour's support base when it hits trouble.

There was a reference to uncertainty and anxiety, but that was in a short passage about economic turbulence, intended to reassure people with the claim that the government has made the right decisions to cut inflation and invest in skills so that Britain is well placed to weather international financial storms.

The speech did not mention Alex Salmond by name, and there was only one mention of Conservatives. The Prime Minister took only a short time to join in the Labour attack on council cuts, which the party is seeking to pin on SNP ministers and councillors. But the main theme running through the speech was a sustained attack on nationalism, by contrasting independence with interdependence.

While speaking from memory, much of his global message lifted long sections from previous speeches to Labour conference. He returned to a familiar theme of the economic threat of China and India, raising their skill levels and training millions of graduates to compete for jobs.

This was in the context of Gordon Brown's treasured theme of children whose potential is not realised, tying together the message of creating opportunity for all with the necessity to train British people to compete in the global economy.

Contrasting this with the case for Scottish independence, Mr Brown asked: "What sense does it make, when there are the great challenges of the future, to erect barriers in this island when what we should be doing is uniting with other countries to make all the difference we could make?

"When some people say the Scots are diminished by having to participate in the United Kingdom, think of it the other way round," he said. With the focus on tackling international poverty and insecurity, he cited the work by Douglas Alexander, International Development Secretary, in the World Bank, Defence Secretary Des Browne in the United Nations security council, and Chancellor Alistair Darling in the International Monetary Fund.

"Here are Scots able to lead not just in Britain but the rest of the world. The union does not diminish our influence. The union enhances the influence of Scots people and Scots ideas and Scots values that can help change the world," he said.

Mr Brown told delegates: "Think of what we have achieved by working together and think whether it makes any sense that in a world where barriers are coming down everywhere, where people are recognising their interdependence, where people understand co-operation is the only way forward for the future, what sense does it make within these islands to create new barriers as the SNP would do, that distance Scotland from the rest of Britain, making it more difficult to trade, travel and play your full part as a citizen of the United Kingdom.

"That is the question for Scotland: do we move backwards to a 19th-century formula to nation states with borders, embassies and consulates, or do we move forward to the interdependent world of the 21st century where people co-operate and work together."

Responding to the speech, SNP Deputy Leader Nicola Sturgeon said: "Labour have learned nothing from their election defeat last year. Gordon Brown came out with the same old scaremongering nonsense that was wrong about the SNP and Scotland when we were in opposition, and is equally wrong now that we are in government".

Tory Shadow Scotland Secretary David Mundell described the speech as "a disjointed and incoherent contribution, perfectly suited to Labour's slump and slumber in the polls. Labour just doesn't get it".