In an interview with Scotland On Sunday, Iain Gray fires an opening salvo singling out personality traits of the First Minister and saying Scotland deserves better than a leader who wears "silly hats" and pulls faces at the camera.
Iain Gray said the First Minister had become an embarrassment as he signalled that he is prepared to fight dirty in next year's Scottish election.
Gray drew attention to a series of recent events and argued that only he had the seriousness to turn around Scotland's economy.
Gray's readiness to insult Salmond is a strong sign that the personalities of the leaders of the two main parties is set to become the dominant theme of the May contest.
Since taking over the Labour leadership Gray has come under fire for not being as charismatic as Salmond or his equal as a speaker.
The SNP has argued that their front bench and leader are far stronger than that led by Gray and are set to make their relative strengths a defining issue of the election.
But Gray believes Salmond's Government has "damaged" Scotland and cost the nation 40,000 jobs by failing to stimulate the construction industry.
"The SNP have been bad for Scotland," Gray said. "In fact, they've damaged Scotland. Let's judge Alex Salmond on his track record. On his watch we have got fewer teachers. We are now losing nurses. We have lost our key infrastructure economic projects and we have seen unemployment in Scotland go from the lowest to the highest in the UK.
"Any Government led by me would have a relentless focus on jobs and ensuring that we have the skills and the opportunity to rebuild."
But Gray reserved his most caustic comments for Salmond's personality.
"What I think the Scottish people don't need at a time like this is a politician like Alex for whom it sometimes seems that photo opportunities in silly hats are more important than taking the serious and hard decisions that are needed for Scotland," Gray said.
Gray was referring to the alleged fashion faux pas of the First Minister when he went to the Commonwealth Games in Delhi in a wide-brimmed blue sun hat. A photograph of the First Minister with a Tunnock's Teacake was also mentioned.
"To be honest with you," Gray said. "When I see the photos of the First Minister in a funny sun hat or making a funny face at a Tunnocks Teacake or going all the way to Copenhagen to try to get a photo with Arnie Schwarzeneggar ...I actually think that's quite embarrassing."
A spokesman for the First Minister disputed Gray's analysis, saying that a recent IPSOS Mori poll of 1,001 Scottish adults showed that 54 per cent were satisfied with Salmond, compared with 39 per cent who were satisfied with Gray.
"Iain Gray must be badly rattled, and no wonder," the First Minister's spokesman said. "The figures speak for themselves - Alex Salmond is as popular now as when he became First Minister, an extraordinary achievement nearly four years into government, with positive approval ratings more than three times those of Iain Gray."
The First Minister's spokesman also disputed Gray's analysis of the economic situation, claiming unemployment was now falling in Scotland, compared with the rest of the UK.
The spokesman said: "We are getting on with the business of government - with employment rising in Scotland and unemployment falling, while both figures deteriorate UK-wide - and exceeding our job-creating renewable energy targets. This is what people are interested in, and why our support is going up. Mr Gray doesn't have anything to say for himself or his party - perhaps because there isn't anything to say."