Alex Salmond has called the UK Government "incompetent Lord Snooties" as he declared it was game on for the independence referendum.
The Scottish First Minister hit out at politicians at Westminster who he claimed were "unwilling to do what is best for Scotland".
With voters north of the border due to vote on the country's future in 2014, Salmond insisted: "Now is the time for Scotland to choose, to seize a different future."
The First Minister used his speech to the Scottish National Party's annual conference in Perth to launch a furious attack on a Westminster Government hit by political woes in the last 24 hours.
Andrew Mitchell stood down as chief whip on Friday after admitting the row over his confrontation with police officers in Downing Street made his position untenable - although he continued to insist he had not called a policeman a "pleb".
Meanwhile Chancellor George Osborne was forced to pay a £160 upgrade for his train ticket after he was caught sitting in first class with only a standard ticket.
To cheers from the audience Salmond demanded: "Why on earth do we allow this incompetent bunch of Lord Snooties to be in positions of authority over our country?"
He added: "Westminster would put this first class nation in the second class carriages."
But the SNP leader declared: "No more second best for Scotland. It is time, it is past time, for a fresh start for our nation."
Salmond told the conference: "Westminster has had its chance and Westminster has fallen short.
"It's not just that in Westminster and London we have a government that is unwilling to do what is best for Scotland. It is incapable of putting the people of Scotland first."
He continued his attack, hitting out at the UK Government's stewardship of the economy and its continued support for nuclear weapons.
"We face a Westminster government that is hell-bent on pulling our society apart at the seams," Salmond said.
"Austerity, a one-way street with tax cuts for the rich and benefit cuts for the poor.
"Billions to be spent on new nuclear weapons while families struggle to heat their homes.
"What kind of brave new world is this?"
In his keynote conference address the Fist Minster declared: "Westminster is beyond salvation."
But he added: "Our social democratic Scotland can still be won."
With the independence referendum taking place in two years he said the choice before voters was clear.
Salmond said: "Scotland can vote no and achieve nothing.
"Or we can vote yes to get the platform that we need."
Although a poll on Thursday showed just 30% of Scots supported leaving the UK, Salmond insisted there was a majority in favour of some kind of constitutional change.
He told the packed auditorium: "Many want independence. Many want more powers. But have no doubt, once again the majority of our fellow citizens are for change."
And he said: "Over these next two years our task is clear. To tell the truth about Scotland and what we can achieve. To proclaim that we have, in ourselves, all we need to truly prosper.
"That is the platform on which we shall win independence for our country."
Salmond insisted if Scotland left the UK it would benefit from an "independence dividend".
He claimed the SNP's defence plans would cost almost £1bn a year less than under Westminster rule, with £230m of that coming from ending payments for the Trident nuclear weapons programme,
And he pledged over the next year Scottish Nationalists would "spell out what that independence dividend can do for services and for jobs".
The First Minister insisted Scotland was "financially stronger than the UK as a whole to the tune of £2.7 billion", saying that while the country paid 9.6% of taxation it received a smaller proportion - 9.3% - of UK Government spending.
He argued: "With access to our own resources we could invest more, borrow less and save for the future, protect services, or a combination of the three."
He described the run-up to the independence referendum as being the two most important years in the SNP's history, announcing his Scottish Government would introduce legislation within the next few weeks to ensure that all 16 and 17-year-olds could vote in that ballot.
The First Minister stressed that the campaign for independence was not just about achieving the party's constitutional objective.
"This referendum is not just about an independent Scotland," he said.
"It is about our belief that for Scotland there can be - there must be - a better way.
"It is about using that power to create a more prosperous economy and a more just society."
Salmond's conference address comes just five days after he signed a deal with Prime Minister David Cameron on the staging of the referendum,
And he declared: "It is game on for Scotland. This referendum creates a once in a generation opportunity"
He hit out at the anti-independence campaign, saying: "Instead of telling people in Scotland what they can do, they tell us what we can't do."
Salmond continued: "Their message is clear enough 'Abandon hope all ye who vote No'."
It was only independence, he insisted, that would protect the gains Scotland had made since devolution, such as the introduction of free personal care for the elderly.
Scottish Labour leader Johann Lamont has recently questioned the continuing affordability of policies such as this and others including free prescriptions and the abolition of tuition fees for Scots studying in the country's universities.
Salmond claimed both Labour and the Tories were "united in a death grip programme to sweep away concessionary travel, free prescriptions and education".
He warned: "What was won could now be lost. Have no doubt what was gained with devolution can only now be guaranteed with independence."
As well as announcing legislation would be brought in at Holyrood to ensure all 16 and 17-year-olds could vote in the referendum, Salmond also told the conference £11m would be spent over the next two years enabling a programme that helps first-time teenage parents to be extended across Scotland.
The Family Nurse Partnership already operates in a number of areas, and has provided intensive support to 450 young mothers and their children.
The First Minister said: "We will ensure the establishment of Family Nurse Partnerships across Scotland by the end of 2015, benefiting thousands of young families and giving some of Scotland's most vulnerable children the best possible start in life."
He also revealed mobile phone giant Three was creating nearly 400 jobs in Glasgow, almost doubling the number of workers at its call centre there.
Salmond hailed this as a "much-needed and welcome boost for the Glasgow and Scottish economies"
But his rivals hit back, with Ms Lamont claiming the First Minister "can't be straight with the Scottish people".
The SNP leader declared on Thursday the "nonsense" of the Union would end in 2014, but the Scottish Labour leader said: "He could end the nonsense now. The nonsense of claiming Scotland would at a stroke be better off with independence when he knows it would push costs up.
"He could end the nonsense of saying Scotland is the country where everything can be free when he has cut local services because he won't fund the council tax freeze.
"He could end the shame of trumpeting free care for the elderly when the reality is many of our old people miss out on the care they need, while others get just 15 minutes care per visit because he won't fund it.
"This is a man who believes in cheap slogans but won't fund the policy behind them."
She continued: "Alex Salmond won't end the nonsense because he can't be straight with the Scottish people.
"Instead he wants to spend the next two years trying to sell a bill of goods to the Scottish people he knows we don't want, while he ignores the real concerns of Scots - jobs, a decent education, proper healthcare and dignity and serenity in old age."
Meanwhile Scottish Tory leader Ruth Davidson said: "This was a lacklustre speech inspired by division and with little substance from a First Minister who clearly has a chip on his shoulder.
"In his cynical attempt to create a wedge between the people of Scotland and their nearest neighbours in the UK, we saw Alex Salmond resort to petty insults and continual accusations of blame aimed at Westminster.
"It was a performance beneath the office of First Minister and showed a man incapable of taking responsibility for his own actions, never mind being trusted to establish a new nation state.
"It may have been well received by his captive audience in Perth, but the people of Scotland won't be convinced by Alex Salmond's bluster."
Davidson accused the First Minister of "using insults as a diversion to run away from serious questions such as how we pay for future services".
She blasted: "It is pathetic. Scots deserve better and if Alex Salmond is so sure of his case for separation then it's about time he stopped playing games and was upfront with voters."