The last six weeks have demonstrated the inherent weaknesses and complacency in the two-party system in the UK.
In different ways, both Ukip in England and the SNP in Scotland are showing what happens when the two main parties take things for granted. The rise of Ukip in England has taken both the Conservatives and Labour unawares, like the proverbial frog slowly and blissfully boiling to death as the water gets ever hotter around him.
Not much more that six months from the next election, and the two major parties are both struggling with the twin demons of internal strife and an insurgency from a nationalist party in their back-yard - albeit in different countries. Things are looking very messy.
The last Englishman standing
Ukip has come a long way in two years: since they first appeared on the by-election radar in late 2012 (as noticeable runners-up) they have gone from strength to strength. Two years ago they were polling well under ten per cent of the vote (around 5% on average); that average has been relentlessly climbing, creeping up like a lethal vine, ever since. For the past six months it's rarely been below 15%, and sometimes higher than 20%.
There are many different reasons for this: but one of the main factors is also the unusual set of circumstances that occurred as a result of this current parliament. With Labour unable to fully capitalise on the government's struggle with the economy whilst in power due to the electorate's recent memory of their last few, miserable years in power under Gordon Brown. Meanwhile, the LibDems, the party that the electorate have usually turned two as the main "protest party" for the last twenty years, are tarnished by the mill-stone of incumbency as the Tories. Their vote share has tumbled from more than a fifth at the last election, to less than a tenth barely six months from the next election.
And where have those "lost" LibDem voters gone? More on that later.
So apart from everything else, Ukip and Nigel Farage are in some ways blessed by being in the right place at the right time. If Ukip didn't exist, it may well have been necessary to invent them, given the peculiar political situation Britain finds itself in after 2010. With all three major political parties considered "damaged goods" in different ways, Ukip have the advantage of clearly standing for values so catagorically at odds with those held by the three main parties: by which I mean immigration and Europe, which Ukip have (successfully) linked to the issue of the economy. By finding "cleavage issues" that give Ukip a very easily-definable "brand", this marks them out from the "drive to the middle ground" that has occupied the minds of the political classes for the last fifteen years.
Add to that Nigel Farage's natural ability to "sound human" compared to the out-of-touch lifestyles of the political establishment in Westminster, and Ukip now look to be a decent bet on grabbing up to ten seats (or more) at the general election. Bear in mind that the last time a fourth party appeared (the SDP in the 1980s), they won less than half a dozen seats. If, as expected, Ukip win the Rochester by-election, other Tories may also (not unreasonably) assess that their chances of holding on to their seats would be improved by changing to Ukip.
This would be the nightmare scenario for Cameron, and would cement the apparent fragmentation of British politics. It would also effectively undo any chance of the Tories winning a majority for the foreseeable future.
But he's not the only one facing sleepless nights. Apart from a potential Ukip insurgency in the north of England (which the Tories are already written off an unwinnable), Ed Milliband has even more serious problems north of the wall...
Our friends in the north
Labour may have won the battle of the Scottish referendum, but they look to be losing the war for Scotland. The recent resignation of the leader of Scottish Labour, Johann Lamont has demonstrated the problem that Labour have fighting off the rise of the SNP in places like Glasgow and Dundee (which both voted "yes" in the referendum).
The SNP now look much like the "real" Labour party in Scotland (in the same way that Ukip look like the "real" Conservative party in England). Psephologists say that there are few real seats where the SNP have a real chance of unseating Labour, but these are strange times. If Ukip can win a seat with a more than 10,000 majority, then it's difficult to say how complacent Labour can deserve to be in places like east Glasgow and Inverclyde. Judging from Johann Lamont's comments, she thinks the Labour party in Scotland has bee treated very badly by its Westminster masters, more or less calling for a separation for the sake of Scottish politics.
More worrying still is the potential fate of the Liberal Democrats in Scotland. Many of their sitting Scottish MPs have the SNP as their main rivals (there are more than ten Lib Dem Westminster MPs in Scotland), and some experts are predicting that most of them will lose their seats to the SNP. If that happens, then not only will it make the Lib Dems a much-reduced force in parliament after the election, but that the SNP may well come from having only a handful of MPs, to potentially a dozen or even more.
And in a hung parliament, the SNP's expanded cohort of parliamentarians could hold sway on some key votes. Well, that's before the issue of EVEL has been factored in. Anglo-Scottish relations may about to become very messy indeed...
A few Green sprouts
The rise in popularity of the Greens is another of the "silent growth" stories in the last year. While not to the same extent as that of Ukip, the Greens look to have, like Ukip, been the beneficiaries of not being one of the "damaged goods" parties. Like Ukip, they have learned that the best way to beat the FPTP system is to copy the model the Lib Dems used twenty years ago: get a good foothold set up in favourable local environments.
The collapse of the Lib Dem vote since the election seems to have benefitted partly Labour, but also partly the Greens, who to some ex-Lib Dem voters look more faithful to some of the tenets of "liberalism" and localism than the Lib Dems themselves.
Due to this, there are now half a dozen seats that the Greens are targeting, with a decent chance of winning some of them.
While not on the scale of Ukip in England nationally, or the sudden spike in SNP potential fortunes, the "Green surge" would be another sign of the fragmentation of the old "two party" model: in 2015, there is now a reasonable chance of there being five parties in England that have more just a few seats in parliament. In the Scottish parliament in Holyrood, this is already the case.
With the way that the electorate are becoming more discerning and articulate in expressing their political whims, Westminster politics may be seeing the beginning of a permanent fragmentation.