Nicola Sturgeon has vowed to end austerity economics at the SNP's manifesto launch at a rock climbing centre in Edinburgh.
Sturgeon said that under no circumstances would the SNP do a deal with the Tories in the event of a hung parliament but would act to embolden a minority Labour government and shift policy to the left.
Although the SNP candidates are only standing in Scotland, Sturgeon said any influence the party gained in Westminster would be used "responsibly and constructively".
If the polls are borne out on 7 May, Labour will be all but wiped out in Scotland, while the SNP will return dozens of new MPs to Westminster. With the chances of a hung parliament still high, the SNP could prove decisive in passing a Labour Budget and gaining new powers for Scotland.
Here are the highlights of the SNP's offer to Scottish voters.
The SNP wants an end to austerity: it will hike spending by 0.5 per cent a year and spend an extra £24bn on the NHS. In total, the SNP are advocating an increase in public spending of £180bn.
Like Labour, the SNP wants to bring back the 50p top rate of tax for those earning £150,000 or more. Despite being a Scotland-only party, it also supports a UK-wide mansion tax.
As a pro-EU party the SNP wants any EU referendum outcome to be supported by each nation of the UK. This is to ensure that no constituent part of the UK can be taken out of the EU against its will.
It's almost certain this would be unacceptable to a Conservative government. However, it could prove the major constitutional change that would push the SNP to call for a second referendum on Scottish independence.
Along with the Greens and Plaid Cymru, the SNP is vehemently opposed to renewing Britain's independent nuclear deterrent and will attempt to block Trident's replacement in the House of Commons.
The SNP supports an annual target for UK-wide housebuilding of 100,000 affordable homes a year.
By 2020 the SNP wants the national minimum wage to rise to £8.70. The party lobbied to devolve power over the minimum wage during the Smith Commission, but was blocked by the other parties.