A warning by Britain's three main political parties that they would rule out a currency union with an independent Scotland has "backfired in spectacular fashion", Alex Salmond has said after a new poll showed an increase in support for independence.

In the first session of first minister's questions in the Scottish parliament since George Osborne ruled out a currency union last week, Salmond accused the chancellor of insulting the intelligence of the Scottish people.

The first minister told MSPs: "Most people in Scotland would feel that George Osborne insulted the intelligence of the Scottish people … The indications we have so far is that the joint enterprise between George Osborne and Ed Balls has backfired on the two Unionist parties in spectacular fashion."

The first minister turned on Labour, the Tories and the Liberal Democrats after a poll in the Scottish Daily Mail showed an increase in support for the pro-independence side in the week since the chancellor's speech. The Survation poll found that 38% support independence (up six points on a poll two weeks ago) compared with 47% who support the UK, down five points. Survation cautions that a direct comparison cannot be made between its two polls because of a change in its methodology.

But John Curtice, professor of politics at Strathclyde University, said that the strategy of the pro-UK Better Together campaign – to create a game changing moment by ensuring that Britain's three main political parties ruled out a currency union on the same day – has failed. Curtice wrote on the BBC website: "The poll's headline findings suggest that, if anything, the 'no' side's stratagem has not only failed to deliver any immediate boost to the Unionist cause, but has actually backfired."

Salmond seized on the Daily Mail as he joked that he was breaking the habit of a lifetime to quote from the pro-Union right wing paper. The first minister dismissed attacks from the Scottish Labour leader Johann Lamont by saying that Labour had inflicted severe damage on itself by aligning itself with Osborne.

He said: "The Labour party have done themselves huge damage by associating with the Conservatives and in particular George Osborne. The reaction of the Scottish people to being told, instructed from on high that our currency – the currency that we jointly built up – actually doesn't belong to us, it belongs to George, is entirely understandable and will be deeply uncomfortable for the Labour party in Scotland."

Salmond was also scathing about José Manuel Barroso, the president of the European commission, who said that it would "difficult if not impossible" for Scotland to join the EU because Spain might block its accession bid. Barroso pointed out that Spain, which fears secession by Catalonia, has blocked Kosovo's membership bid because it broke away from Serbia. Salmond highlighted remarks by Jim Currie, a former director general for environment directorate at the European Commission, who described Barroso's remarks as "extremely unwise" and "inaccurate".

The first minister said: "Perhaps the comparison between Scotland and Kosovo was not the wisest comparison to make by Mr Barroso. Scotland, [which] has been part of this EU for 40 years, [which] has built up rights and entitlements as part of that structure, [which] conforms to the democratic imperatives that the EU represents – of course we are entitled to our rights as European citizens. The idea that the rest of Europe is wanting to deny us these rights is a total illusion cooked up by the Unionist parties. Scotland is a European nation, we will continue to be a European nation."

Salmond also repeated his warning that an independent Scotland would decline to assume its share of the UK's liabilities if the remainder of the UK declines to agree to a currency union. "The implication, in fact the certainty, is that if you argue – as the UK government is now doing – that they are continuing state, that they keep all of the assets of the UK then it follows, as night follows day, that the end up with the liabilities."

Johann Lamont, the Labour leader who pointed out that David Bowie has "come out for the union", said: "The rest of the United Kingdom, including Carwyn Jones, have said they do not want a currency union. You can't make them have a currency union if you are not in the same country. What does the first minister not understand about his proposal to take Scotland out of the UK? It has come to this: the Scottish government is prepared to deny, deflect, assert and insult in order to win this referendum."