Alex Salmond branded 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, Mr 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 on Friday stood down as chief whip 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 Mr 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."
Mr 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."