Alex Salmond will try to wrap the pro-independence Yes campaign in the mystique and romance of Robert the Bruce and Scotland's 14th-century battle for independence by using the location of the historic "Declaration of Arbroath" to make a slightly less glamorous "declaration of opportunity".

In a visit to Arbroath Abbey today, where in 1320 nobles asserted that Scotland had always been independent and only the people of Scotland could decide who ruled over them, the First Minister will claim that only a breakaway from union with England can release the potential of the "talented people of this country". He will focus his address on the protection of the NHS, an escape from Westminster cuts and the opportunity for young Scots to build a future in an independent state.

As Mr Salmond prepared to remind voters of Scotland's historic battles against English forces and the signature of Bernard, the abbot of Arbroath, on the declaration, he found himself battling a different abbot – Tony Abbott.

The Prime Minister of Australia was holding talks in London with Philip Hammond, the Defence Secretary, when he said "it was hard to see how the world would be helped by an independent Scotland", adding those who wanted to see the break-up of the UK "were not the friends of justice or freedom".

Mr Salmond attacked Mr Abbott's comments as "offensive, foolish and hypocritical", saying "independence does not seem to have done Australia any harm" and that the public intervention by a "naturally gaffe-prone" politician would probably boost the Yes vote. "Who is Mr Abbott to lecture Scots on freedom and justice?" asked Mr Salmond.

Mr Abbott's opinion on the outcome of the referendum, which is now four weeks away, is the most direct one given by an international politician. Previously President Barack Obama said that the United States had a "deep interest" in making sure the United Kingdom remained united.

Alistair Darling, the leader of the Better Together No campaign, said in a speech in Lanarkshire yesterday that attempts by Scotland's Deputy First Minister, Nicola Sturgeon, to recruit former Labour supporters by claiming only "independence would reclaim their politics and their party", were "cynical".

Mr Darling, whose reputation has soared after he soundly beat Mr Salmond in the first televised head-to-head debate, told the audience: "What he is asking Scotland to vote for is austerity-plus for decades to come. The pitch to Labour voters that there would be fewer cuts and more wealth redistribution in a separate Scotland is so cynical."