There have been two main developments since the coming of the Coalition in May 2010 in terms of voter movement - one has been the switch of around 40% of the 2010 Liberal Democrat vote to Labour while the other has been the emergence of the United Kingdom Independence Party (UKIP).
UKIP, which draws its support mainly but not exclusively from the Conservatives, has taken on the traditional role of the Liberals and Liberal Democrats in past periods of Conservative Government - that of a mid-term "protest" vote for disillusioned and disappointed Conservative voters.
The 1970 Conservative Government faced a huge swell in the Liberal vote from the 7.5% nadir of the June 1970 election. By 1973, seats like Berwick and Sutton were falling to the Liberals on huge swings and in the years after Margaret Thatcher came to power in 1979, the Liberals scored huge wins in Crosby and Croydon. UKIP hasn't of course won a by-election yet but has put up some useful if rather unavailing performances.
Unlike the mid-term Liberals, however, the senior ranks of UKIP bristle with ex-Tories who, for whatever reason, could not remain in a party led by David Cameron.
UKIP has moved beyond its basic raison d'etre which was as a party campaigning for British withdrawal from the European Union (EU). While that is still a key tenet, UKIP has tried to broaden its mass appeal into areas such as immigration and social policy.
Yet at the heart of all this is an unwavering populism playing on fears, misconceptions and half-truths. The EU is bad, immigration is bad, foreigners are bad, the world is bad...well, not quite but the post-financial crash insecurities of many are fair game to a populist party that has no answers but is quite happy to poke at the wounds.
After all, not ALL foreigners are bad - the nice Polish girl at the coffee shop who serves your skinny latte is all right and the wealthy Americans who come here are wonderful but we don't want all these horrible Romanians - I mean, they're not like us, are they, all crammed into one house ??
In the end, populist parties succeed only in climates of fear and insecurity. Most of our newspapers peddle little other than celebrity gossip or fear and it's little wonder that in the world as it is, it's easy to find a scapegoat to blame for everything that's perceived as "wrong". It's also incredibly hard to argue against fear - facts, as Nick Clegg discovered in the European debate recently, are no antidote to the barrage of fear-driven half-truth that shrouds the European question.
Ultimately, as we know, prosperity shines a light into the darkest corners and when or if better times return, UKIP will be as the snowflake on a June day but for now this party of meaningless protest which offers nothing and whose only currency is the language of insecurity, remains a potent force.