´óÏó´«Ã½

Many people have been trying to work out what the implications will be for Wales of the extraordinary rise of the SNP.

It seems clear now that it has not led to any noticeable groundswell towards Welsh independence.

Our poll this week put it at 6%.

But for Plaid the answer is much more about the hard-nosed political arithmetic arising from a huge potential increase in SNP members of Parliament.

Plaid have committed to being part of a negotiating block with the SNP and the Greens in the event of a hung parliament.

It means that some of their demands (in this case for an extra £1.2bn for the Welsh government) could be given the kind of consideration that would never have been the case otherwise. In other words it gives Plaid a degree of relevance in a general election campaign.

The problem with the message that it could hold the balance of power is that it is essentially speculative.

It only works so long as there's a hung parliament, it's Labour and not the Conservatives which are the biggest party, the arithmetic works and they're not cut adrift by the SNP.

A number of things have to come together and the question is whether it's a strong enough message to win support from floating voters in places like Llanelli.

There are other strands to the Plaid message such as anti-austerity, but I suspect the balance of power argument is the one that will get the most airtime and headlines in Caernarfon.

If there is a hung parliament the strength of the relationship between the two nationalist parties will be key, particularly as the SNP are highly likely to dwarf Plaid on the numbers.

It would be fascinating to know what kind of discussions have been going on behind the scenes between Leanne Wood and Nicola Sturgeon.

The Barnett formula has been an obvious area of dispute. The SNP are committed to it while Plaid want it scrapped.

Plaid say things have now moved on because the formula's future was guaranteed in the referendum campaign.

And even if the SNP don't need Plaid's MPs to cut a deal with Labour, the parties have very close historical connections which are likely to play a part.

As well as retaining its three seats, Plaid are looking to push Labour hard in Anglesey and Llanelli and the Liberal Democrats in Ceredigion.

Read on over the next few days as I outline how they're planning to do that.