SNP leader Nicola Sturgeon has insisted Scotland will no longer be "sidelined or ignored" at Westminster after her party won an unprecedented 56 seats in the general election, sending political shockwaves across the UK.
The First Minister said the landslide victory - which saw the SNP claim all but three of the constituencies north of the border - had given the nationalists a "mandate on a scale unprecedented for any political party, not just in Scotland but right across the UK".
Half of those who voted in Scotland backed the SNP on Thursday, with the party winning 1,454,436 votes across the country.
While that has resulted in a record number of nationalist MPs at Westminster, it remains unclear how much influence they will be able to exert after David Cameron's Conservatives won a shock majority government.
But as she gathered with her group of MPs, Ms Sturgeon said they would now be pressing for an end to austerity.
She insisted: "Our message to Westminster is simple, our message to the politicians of the other parties at Westminster is this one - no longer will Scotland be sidelined or ignored in Westminster.
"Our voice will be heard. Our interests will be protected."
The First Minister, whose party had had just six MPs after the 2010 election, stated: "Scotland has given the SNP a mandate on a scale unprecedented for any political party, not just in Scotland but right across the UK.
"We will use that mandate to speak up for and protect the interests of Scotland.
"Let us be very clear, the people of Scotland on Thursday voted for an SNP manifesto which had ending austerity as its number one priority, and that is the priority that these men and women will now take to the very heart of the Westminster agenda."
Ms Sturgeon said: "After Thursday, and as I told the Prime Minister when I spoke to him yesterday, it simply cannot be and it will not be business as usual when it comes to Westminster's dealing with Scotland."
'Our job is to repay the trust you have shown in us'
Ms Sturgeon said she was "absolutely delighted" and "bursting with pride" at her party's massively expanded group of MPs.
"The people of Scotland have spoken and the people have placed their trust in the SNP to represent Scotland at Westminster as well as at Holyrood," she said.
"Just as voters in almost every part of this nation of ours chose the SNP our pledge is that these 56 SNP MPs will represent the interest of all of Scotland.
"We will represent in Westminster, just as we do in the Scottish Parliament, people in every corner of our country, people who voted Yes in the referendum as well as people who voted No. People who voted for us on Thursday and people who did not.
"Our job is to repay the trust you have shown in us and I pledge today that that is exactly what we will do."
She said in the general election Scotland had spoken "more loudly and more clearly than ever before" and added: "My message today to Westminster is this - Scotland's voice will be heard in Westminster now more loudly that it has ever been before."
She continued: "As we promised in the campaign that strong voice will be a voice for more progressive politics.
"We will continue to seek to reach out to people of progressive opinion right across the UK, so we can put an end to austerity, invest in our public services like our precious National Health Service, invest in a stronger economy to get more young people into jobs. We will work with others to put those priorities right at the heart of Westminster.
"That is what people in Scotland have tasked the SNP now with doing."