Former Prime Minister Sir John Major is to claim that a Labour government supported by the SNP would be a “recipe for mayhem”.
Sir John will use a speech in the Midlands to say a Labour-SNP government would mean families paying with “higher taxes, more debts and fewer jobs”.
He will say a future Labour government would be subjected to a “daily dose of blackmail” from the nationalists.
But Ed Miliband told the BBC “that ain’t going to happen”.
With 16 days to polling day, Sir John will say that, in practice, Mr Miliband would be forced to agree to the nationalists’ demands or face the collapse of his government.
‘Slowly but surely’
“If Labour were to accept an offer of support from the SNP, it could put the country on course to a government held to ransom on a vote-by-vote basis,” he is expected to say.
“Labour would be in hock to a party that – slowly but surely – will push them ever further to the left. And who would pay the price for this? We all would. We would all pay for the SNP’s ransom in our daily lives – through higher taxes, fewer jobs, and more and more debt.
“This is a recipe for mayhem. At the very moment our country needs a strong and stable government, we risk a weak and unstable one – pushed to the left by its allies, and open to a daily dose of political blackmail.”
But interviewed by Evan Davis on the BBC, Mr Miliband – who has rejected a Labour-SNP coalition – rejected claims that the SNP would “call the shots” in the event of a hung parliament.
“That ain’t going to happen; that ain’t going to happen,” he said.
In other election news:
- Labour would launch an emergency recruitment drive to get 1,000 more nurses into training this year if they win the election
- Nick Clegg has said owners of second homes in rural beauty spots could pay double the rate of council tax under Liberal Democrat plans
- The Democratic Unionist Party launches its manifesto
- The BBC should be “cut back to the bone” and the licence fee reduced by two thirds, according to UKIP’s Nigel Farage
Policy guide: Key priorities
What are the top issues for each political party at the 2015 general election?
Launching her party’s manifesto in Edinburgh on Monday, SNP leader Nicola Sturgeon sought to allay the fears of some English voters, insisting they would act “responsibly and constructively” in the interests of the whole of the UK.
Recent polls all point towards there being a hung parliament after 7 May, and suggest the SNP could be the third largest party and crucially hold the balance of power.
As a consequence of this, the “threat” of an SNP link-up with Labour has emerged as a major Conservative line of attack in the election campaign.
But the BBC’s deputy political editor James Landale said Sir John has long opposed Scottish nationalism, warning before the 1997 election that voters have 72 hours to save the union.
“Almost 20 years on, he is once again banging the same drum,” he said.
The Conservatives are determined to keep up these warnings to bring any wavering voters back to the Tory fold, our correspondent said.
“But Labour believes the Conservatives are themselves putting the union at risk, by acting as cheerleaders for the SNP,” he added.
It is a view echoed by the former Tory Scottish Secretary Lord Forsyth who told The Guardian newspaper that his party was playing a “short term and dangerous” game by building up the SNP.
“We’ve had the dilemma for Conservatives, which is they want to be the largest party at Westminster and therefore some see the fact that the nationalists are going to take seats in Scotland will be helpful,” he said.
“But that is a short-term and dangerous view which threatens the integrity of our country.”
But despite this Sir John will say that the SNP’s “driving ambition” is an independent Scotland, and it would use its position to demand policies that favour Scotland at the expense of the rest of the UK.
“That is no way to run a country. And nor is it remotely fair to England, Wales and Northern Ireland,” he will say.
Meanwhile, former Labour minister and London mayoral contender David Lammy told ITV that his party could “do business” with the SNP after the election.
He said: “I still think Labour can form the next government and that’s what I am fighting for. But yes, there is common ground with other parties and the SNP would be included in that and we may need to enter into discussion after the general election”.