The Better Together campaign leader accuses Alex Salmond of putting his ego before Scotland's interests and says the First Minister would have had to resign over the EU legal advice row if he had been at Westminster, saying: "He'd have gone. Down here, you would never have got away with that."
In an interview to mark one year to go to the 2014 referendum, Mr Darling rejects the SNP charge that the No camp is basing its entire campaign on fear and negativity, arguing Mr Salmond and his colleagues are losing the argument and reverting to bluster and diversion.
He declares: "The more they don't answer questions, the more we're going to come after them. They're not going to get away with this idea that if you criticise us you are not speaking up for Scotland.
"I am speaking for Scotland. I care passionately about Scotland. I'm not going to see Scotland sold short. I'm certainly not going to see Scotland sold a pup and that's what it increasingly looks like we're being sold."
The former Chancellor says Mr Salmond is all about personal status but is now "struggling" because people are increasingly unwilling to accept his bold claims as they once did.
He claims the SNP leader's fight is "increasingly with his own people" because it is "the first time a lot of Nationalists have seen these economic arguments and the more they look at them, the more they think 'what on earth are we signing up to?'"
Mr Darling also upbraids Mr Salmond for accusing Mr Cameron of being anti-Scottish, saying: "The idea that if you disagree with him you're anti-Scottish is not only arrogant, it's totally unacceptable for someone who is First Minister."
With Scottish Labour having denounced Mr Salmond for implying Mr Darling was the "monkey" to Mr Cameron's "organ grinder", the No campaign leader suggests his opponent is focusing on the Prime Minister to distract voters away from the core issues of the campaign.
He says: "He wants (to debate with) Cameron because that's purely an act of displacement, a distraction because he wants to make it a Scotland-England contest.
"There is a lot of evidence now that a majority of people in Scotland think Salmond is putting his own political interests above those of Scotland and that is something he should reflect on."
But asked if the Conservative leader was a help or a hindrance to the No campaign, Mr Darling replies: "Neither. Cameron himself said he would prefer the Union to continue but it's a matter for Scotland and he's dead right."
He then adds: "Cameron, for this argument, is neither here nor there. This is an argument we have to have out in Scotland."
The Edinburgh MP also berates signs of triumphalism in Whitehall - where senior sources have already claimed victory - denouncing this as "absolute rubbish" and insisting the polls in the coming months will narrow.
He adds: "It's all to play for. It will be a lot closer than people think because the headline polls are misleading. It will be difficult to call right up to the wire."
Elsewhere, at the Liberal Democrat conference in Glasgow, Danny Alexander will today warn a Yes vote would cost tens of thousands of jobs.
The Chief Secretary to the Treasury is due to say: "In the end, nationalism is all about building barriers between peoples, whatever the cost; liberalism is about knocking those barriers down.
"Our job, from now until the day of the referendum, will be to demonstrate why Better Together isn't just a slogan but the truth. Tens of thousands of jobs in Scotland depend on us winning that fight.
"For the sake of our country, our children, and our grandchildren, we cannot, must not and will not lose."
A Yes Scotland spokesman said it was an example the No campaign's attempt to panic and "scaremongering" tactics.
He added: "Mr Darling really needs to stop trying to reduce the debate about Scotland's future to the level of personalities and party political mud-slinging. The people of Scotland deserve better than that.
"A glance at the Yes Scotland website will show that we are constantly answering questions about why a Yes vote is the right choice for Scotland.
"Our thousands of volunteers and ambassadors will also tell you why more and more people are coming to Yes."