17/11/2013 17:32 GMT | Updated 23/01/2014 18:58 GMT

Ed Miliband Can't Lose

It is bandied about by the press that the 2015 general election will be competitive. Naturally, sustaining such a narrative sells papers. However, when observing the statistics with an impassive and unpartisan mindset, one realises that not only is the general election Labour's to lose; it is almost inconceivable that the party could lose it.

I will detail why this is the case in a minute, but first let's recap where the two main parties found themselves in 2010. Labour suffered its second heaviest defeat since 1918, clinging on to 29% of the vote. The Party was led to that hammering by a leader who was, polls suggested, considered by voters to be discredited and weak. In contrast, the Conservative Party and its leader had been showing strongly in the polls, ever since David Cameron challenged Gordon Brown to call the 'election that never was'. Despite this, when the election was finally held, in May 2010, the Conservatives only managed to secure 36.1% of the vote, equating to a 5% swing from Labour since 2005. To put this in context, the swing from the Conservatives to Labour, in 1997, was 10.3%.

Therefore, the obvious question is this: how can the Conservatives realistically hope to win a majority in 2015, if they failed to do so in 2010, when the political landscape was vastly more favourable?

The answer - to be blunt - is that they can't. The Labour Party only needs a lead over the Conservatives by 2% to form a majority government. Moreover, Labour could trail the Conservatives by 3% and still be better placed to form a coalition. The Conservatives, in contrast, need a 7% lead over Labour before they realistically start to enter majority government territory (assuming that there is no or little recovery in the Lib Dems' polling - if there is a recovery, the Tories will need to lead Labour by 11%). However, a 7% lead would provide such a wafer-thin majority that another coalition or election would likely be required.

I should add that my model presumes UKIP's share of the vote will be 5%, which is much less than the vast majority of polls have been showing. Every percentage point increase in their support would disproportionately affect the Conservatives and increase the lead they need over Labour to form a majority government.

The next obvious question is whether it is likely that the Conservative Party will emerge from the other side of the election with a lead of at least 7% over Labour?

The answer - again - is no. Whilst this would represent no swing from 2010 - and, therefore, may seem perfectly obtainable - the mountain to climb is even steeper this time around. This is because of the huge increase in Labour's support - regularly in the 38-42% bracket - from the historically low base recorded in 2010. Therefore, a 7% lead for the Tories would require Labour's support to drop, for argument's sake, to 33% and their own to increase to 40%. Most polling companies, in most polls, have not shown the Tories poll so highly, or Labour poll so low, for the vast majority of this parliament. I cannot see any factor reversing this current trend.

This lack of confidence in the Tories forming a majority government, post-2015, is supported by the Electoral Calculus website - the most accurate predictor of the 2010 election result - which puts the chance of the UK having a Labour majority government at 81% and the chance of having a Conservative majority government at 4%.

And the fact that Labour could come second in the popular vote and still form a government makes redundant the criticism from some commentators that an 8-10% poll lead is not good enough - it would provide a very healthy majority of 90+ seats, which is vastly superior to the majority Tony Blair secured at the 2005 general election.

Moreover, an 8-10% poll lead should not be pooh-poohed for another reason - historical precedent. The last time an opposition party returned to government at its first attempt was in February, 1974. Indeed, what Ed Miliband is trying to achieve is unprecedented in recent times and, as a result, means that he cannot be expected to secure the massive leads Tony Blair's New Labour once enjoyed.

Anyway, national voting intention, while an important tool in predicting the outcome of an election, is a blunt one. What really matters is leads parties build up in marginal seats - where elections are either won or lost. And it is in these marginal seats that Labour is outperforming its national vote share. Lord Ashcroft's most recent polling of the Conservatives' 40 most marginal seats (conducted September 2013) suggests that Labour has a 14% lead over the Conservatives - a lead which has grown by 5% over the past two years and would result in Labour winning all 32 seats in which it is in second place to the Conservatives. No wonder Lord Ashcroft has said that Labour will win in 2015.

Such a lead for Labour in the marginals is vital because psephological precedent tells us that newly installed incumbents (especially if they're from the main opposition party) are harder to dislodge and, therefore, a greater swing is needed than that required, nationally.

However, there might be a colossal revival in the Conservatives' fortunes before the next election. Indeed, the governing party almost always makes up lost ground as election day approaches (apart from in 2005, interestingly).

And the positive news for David Cameron and George Osborne is that they are consistently shown to be viewed as more competent on managing the economy than Ed Miliband and Ed Balls. This is significant because no party, in recent times, has lost an election whilst leading in the polls on economic competence. In 1979, for instance, James Callaghan was vastly more popular than Margaret Thatcher, but the Conservative Party was viewed by the public to be the party of competent economic management. The result: a Conservative victory.

Whilst this appears to be positive news for the prime minister and chancellor, it should provide scant comfort. This is because the Conservatives don't just need any old poll lead; they need a 9-10% poll lead in order to begin to form a strong and stable government. And if a 7% poll lead looks overoptimistic, then a 9-10% lead almost certainly is.

As I said at the outset, not only is the general election Labour's to lose; it is almost inconceivable that they could lose it.