Former Prime Minister Sir John Major has warned a minority Labour government propped up by SNP votes would be a "recipe for mayhem".
In a speech in the Midlands today, Sir John said it would lead to a "weak and unstable" administration which would wreck Britain's economic recovery.
The Scottish Labour leader Jim Murphy has criticised David Cameron and Sir John Major over their attacks on the SNP.
Campaigning in Glasgow today, he said:
SNP leader Nicola Sturgeon could present a potentially long-term problem for Labour.
Sir John will give a speech later today saying a Labour-SNP government would be "weak and unstable" and wreck Britain's economic recovery.