In a hardening of the party’s warning that an SNP vote could lead to a Conservative victory, Ms Curran suggested that backing for the Nationalists rather than Labour may have the most far-reaching consequences in decades.
Ms Curran issued the stark warning as Scottish Labour continues to trail the SNP in opinion polls ahead of May’s election, with the Nationalists on course to make sweeping gains.
The MP for Glasgow East said Labour could not take any votes for granted in its bid to oust David Cameron from 10 Downing Street, as she admitted her party must “start rolling up our sleeves and arguing on the issues”.
Ms Curran said Scotland and the UK face the “biggest spending cuts of any major advanced economy” in the world, as she launched a document on living standards – in a direct pitch to left-leaning voters tempted by the SNP on 7 May – during a campaign visit to Rutherglen yesterday.
Ms Curran warned that another five years of the Conservatives would mean further cuts, as the party’s document outlined what it said was the impact of the policies of Mr Cameron’s government on living standards, the low paid and the economy.
Labour said that working people across Scotland are £1,600 a year worse off since 2010, and that 11,000 people are paid less than the national minimum wage of £6.50 for over 21s.
The shadow cabinet minister suggested that, for the first time in postwar Britain, the unintended consequence of an SNP vote could tip the balance in a general election seats and hand the Conservatives a Commons majority.
She said: “The general election in May will be the 15th of my lifetime, but it’s the most important one yet.
“We will either elect a UK Labour government that will stand on the side of working families or get landed with a Tory government that stands idly by as Scots struggle to make ends meet.
“Scots know that the largest party across the UK will form the next government. It has been that way in every election since before the Second World War.
“Any seat the SNP take from Scottish Labour will only increase the chances of the Tories being the largest party across the UK and therefore the next government.
“We could end up letting David Cameron back into power by accident.”
Ms Curran also insisted Labour is “not scaremongering” with its core message that voting for any other party on 7 May could keep the Conservatives in power across the UK.
However, SNP Westminster leader Angus Robertson hit back, claiming that sending a large block of Nationalist MPs to Westminster would not prevent a Labour victory and would push a government led by Ed Miliband to the left.
Mr Robertson said: “By electing SNP MPs, the people of Scotland can vote to get rid of the Tories, protect the welfare of everyone who lives here, and promote progressive politics across the UK.
“Left to their own devices, Labour have already made clear that they would continue with the Tories’ failed austerity economics which are causing hardship in communities across the country while spending £100 billion on new weapons of mass destruction.
“This is why we need a strong team of SNP MPs holding the balance of power – ensuring Scotland’s priorities become Westminster’s priorities and forcing a rethink on a range of disastrous Westminster policies.”