With all the opinion polls of 2014 now in, how have the four main UK parties ended the year?

Labour will take heart from the slight rally it experienced in the two weeks before Christmas, which was big enough to ensure its average score for December was 0.2 points up on that for November. It also meant the party finished 2014 1.8 points ahead of the Tories:

As you can see, the gap between Labour and the Tories widened a little in December, after reaching its narrowest point of the year in November.

But Labour ended the year almost five points below where it began. Yes, it’s not been a consistent decline. From May to August the party went up in the polls, before resuming a descent. Nonetheless the overall trend has been downwards and it is one that has changed profoundly many people’s expectations for the election result. At the start of the year it would have been fair to assume Labour was heading for a majority in parliament. At the end of the year it would be wise to assume anything but. The party’s average for December (33.4%) is its second lowest monthly score since 2010.

If the Tories feel at all thrilled by the sliding fortunes of its immediate rival, they should pause and focus on their own poll performance. They began 2014 on an average of 32.3% and ended it on 31.6%. Throughout 2014 the party showed a stubborn resistance to any significant movement in the polls, either up or down. The trend has been largely static. Remember the Tories need to be at least six points ahead of Labour to end up the largest party in the next parliament, and at least 10 points ahead to be sure of winning a majority.

As this next graph shows, the Tories have not been as low as 31.6% since July 2013, when they were on 31.5% and climbing up from an all-time low of 28.9%:

That graphs also shows how Ukip has seen its support increase in fits and starts over the past 24 months. The party began 2013 behind the Lib Dems, but that didn’t last long. Ukip finished 2014 on 15.5%, slightly down on its all-time high of 16% in October.

For the Lib Dems, 2014 was simply case of endless appalling poll scores. They ended the year on their lowest monthly average for this entire parliament: 7.6%. I honestly thought they had touched the bottom in May when they dipped below 9% for the first time. But instead the slump has continued. How much further have they left to fall?

They are undoubtedly 2014’s big poll loser. Labour does not qualify to be the biggest loser because its decline has not been a) consistent nor b) left the party trailing behind the Conservatives. Its poll trend continues to suggest that it will be the largest party in a hung parliament: something I’ve predicted on this blog from the beginning, and which I still believe to be the most likely outcome in May.

Ukip can be pleased its poll ratings have moved on an upwards trajectory in 2014, unlike in 2013 when they bounced high after the local elections then flopped back. But the party still hasn’t reached what the great psephologist Bob MacKenzie used to call “take-off point”: a poll rating high enough to guarantee a solid block of gains at the election, rather than the odd seat here and there.

With the Tories also stuck below the level they need to be to ensure a critical number of gains, it’s really the case that 2014’s poll trends have served all four parties with more bad news than good.

The two parties sitting immediately below the Lib Dems in the UK-wide poll rankings, the Greens and the SNP, have had a different year. Both hope the polls hint at only good things in 2015. Both will need a great deal of momentum to make real progress within an electoral system biased against small parties, however. In the SNP’s case, the challenge is the enormous swings needed to gain even a handful of seats. For the Greens, it is simply persuading enough voters to double the party’s representation in the Commons from one to two.

Poll trends thrive on their own narratives. They also provide one perspective on the state of British politics – but only one. They do not foretell the result of the election, nor do they dictate it. When the pollsters crank back into action in January, their findings will continue to tell us a little about the state of the nation’s mood, but next to nothing about the 650 contests that will decide the identity of our next government.