Gordon Brown yesterday championed his government's record on helping the low-paid but in doing so made only the briefest of references to his controversial decision to abolish the 10p income tax rate.

Speaking to the STUC's annual congress in Inverness, the Prime Minister told delegates: "We have done more as a government in the last 50 years for poverty than any other government.

"I can say today that as a result of what we have done - and I know there is a debate about 10p taxation - three million families with children since 1997 are £80 a week better off. Two million pensioners, because of the pension credit, the winter allowance, and everything else we have done, including free TV licences, are £40 a week better off."

Referring to the dramatic injection of £50bn into the financial markets by the Bank of England, he told conference how the UK Government was determined to protect British workers against the effects of the "turbulence" in the global markets.

The £50bn was intended, he explained, to "get markets working again in a way that we can ensure that jobs can be continued and that businesses can have the finance they need".

The PM - the first in a generation to address the congress - pledged to do "everything in our power" to move the economy forward, to ensure there was finance to help first-time buyers get on the property ladder and to ensure those on fixed-rate mortgages moving to variable-rate ones were able to afford to do so.

Mr Brown spoke without notes and paid tribute to his hosts, declaring how trade unions were a central part of Scottish life and a "rock for social justice".

He delivered an impassioned defence of Labour's achievements in power with references to more trade union recognition, maternity and paternity pay, and an expansion of childcare and education.

Mr Brown denounced exploitation in the workplace and insisted he wanted an agreement on the long-running issue of agency workers and their employment rights.

The PM also referred to workplace illnesses, receiving applause when he told delegates: "Because any form of asbestosis and mesothelioma is unacceptable, I want us also to find a solution to the problem of pleural plaques."

On jobs, he focused on the long fight against unemployment, pointing out how 270,000 jobs had been created in Scotland. "I am determined that in the next few years we go further and faster towards full employment in our country; that we not only create jobs but good jobs, well-paid jobs, decent jobs."

Yet the loudest applause came when he told the conference: "We support those South Africa dock workers refusing to allow guns into South Africa that could be used against the people in Zimbabwe."

With an eye to First Minister Alex Salmond's appearance before the STUC today, Mr Brown used much of his speech to urge trade unions to consider how Scotland could achieve more as part of the UK in tackling global problems. "Think what we can achieve in the future together," he said, holding out the prospect of education for every child and eradicating diseases.

He contrasted actions taken by the Labour government in London to those of the SNP administration in Edinburgh.

"While the Scottish administration is cutting expenditure on the under-fives, we are determined to expand expenditure.

"While schools are not being built in Scotland as a result of decisions made by the Scottish administration - compared with us renovating or opening a new school every week - we are determined that we will invest properly in the future of our children."

While education maintenance allowances were being cut in Scotland, Labour supported them for every teenager who wanted to stay on at school and Labour would continue to "push forward" a bid to create more modern apprenticeships in Scotland, insisted Mr Brown.

He also used a reference to Scotland's shipbuilding industry as an example of what could be lost if the UK was broken up. "Everybody knows that the shipbuilding industry in Scotland depends to a large extent on the naval orders that include the aircraft carriers. I am determined that the aircraft carriers come to the Clyde and to Rosyth to guarantee the future of our shipbuilding yards there.

"Are we held back by being part of Britain? Are we diminished by being part of Britain?" the Prime Minister asked his audience.

"The shipbuilding industry in our country is stronger because we are part of that British industry," he declared.

"And financial services employed 120,000 in Scotland, with 100,000 of those jobs depending on sales to the rest of the UK. Take that away and you lose thousands of jobs as a result," he added.