Has Miliband Wriggled Out Of Salmond's Pocket?

A giant Alex Salmond glances down towards his suit pocket, where a gormless looking Ed Miliband peeks out. As political photoshop jobs go, it's particularly cruel.

I've lost count of the number of times I've seen the Conservative commissioned image; it's plastered all over the internet.

The message is clear: Vote Labour, Get SNP.

Today Ed Miliband has wriggled out of the jacket pocket: he's ruled out a coalition with the SNP.

It's smart politics, and in reality the Labour leader had little choice.

As the Tories behind the attack ad know, the thought of the SNP in Government south of the border is a frightening prospect to many voters in England and Wales.

What would be the pound of flesh the SNP would demand in return for propping up a Labour government?

In addition, Scottish Labour MPs desperately fighting off challenges from a resurgent SNP were getting increasingly twitchy about their party's refusal - until now - to rule out a formal pact.

Their best line of defence against SNP opponents is "Vote SNP, Get Tory."

If the SNP and Labour are prepared to join forces after the election, that argument becomes redundant.

So today's announcement will be, on the whole, welcomed by Labour members.

However, there are two quick caveats.

Mr Miliband has ruled out a formal coalition arrangement - but not a looser agreement.

The SNP and Labour could form a "confidence and supply" deal, for example, where the smaller party agrees to support the larger on crucial votes such as the Budget.

And, what is smart politics before an election may not look quite so cunning afterwards.

If the polls are anything to go by, the result is likely to be scrappy and uncertain. If Mr Miliband is more able to form a solid, stable coalition than David Cameron, that could edge him closer to the doors of No 10 - even if the SNP are uncomfortable bedfellows.