Nicola Sturgeon called David Cameron "pig-headed" as she brought the SNP's annual conference to a close.
Speaking to a packed hall of party members in Aberdeen, Sturgeon provoked laughter by joking about the allegations from last month that, as a student, Cameron put a "private part" of his anatomy into a dead pig.
She said Cameron has ignored the wishes of people in Scotland since last year's independence referendum and that his attitude towards Scotland was "arrogant, patrician, and out of touch".
"Ever since David Cameron stood on the steps of Downing Street the morning after the referendum and told us that Scotland's expression of self-determination was really all about English votes for English laws, he and his government have treated Scotland with disdain," said the first minister.
"Pressing ahead with austerity, despite 50% of people in Scotland voting for an anti-austerity party, and voting down amendment after amendment to the Scotland bill against the views of the vast majority of Scotland's MPs.
"In fact, the prime minister's attitude to Scotland betrays the worst characteristics of his government – arrogant, patrician, and out of touch. Pig-headed some might say."
Sturgeon went on to warn the Conservative party, which she said is "shifting sharply to the right", that more and more Scots are realising "the only real and lasting alternative to Tory governments" is independence.
"I have a message for the prime minister today," said the SNP leader. "Ignore Scotland at your peril. Know that people are watching and listening, and remember this: It is not you who will decide the future of our country.
"It will be the people of Scotland who decide the future of our country."
However, she said that, while the SNP will always aim for independence, there is more to be done to persuade people that leaving the UK is the right choice for the future of Scotland.
"If we want Scotland to be independent – and we most certainly do – then we've got work to do," said Sturgeon. "There are no shortcuts, we must build the case and make it stronger, convince those we didn't convince last year, and persuade a majority of Scots of what we already know to be true.
"Independence is the best future for Scotland."