The latest polling looking into which issues voters consider to be most important suggest that the prolonged deadlock of voting intention for the General Election may soon, finally, break.

Here’s why:

There are two core issues of which the Conservatives and Labour perform best, the Economy and the NHS respectively. Whilst many other public issues have been vulnerable to attack by other parties over the last five years, the Tories and Labour command mammoth leads in these two most important of areas. The latest “Most Trusted Party” figures for the Economy are 39% to 21%, with the NHS 23% to 39%.

39% a piece for the main two parties – a score high enough to win a General Election outright, if enough voters are convinced to hold that issue as the most important when they enter the polling booth on May 7th. This embodies the grand hopes of the main two parties, but of course, things aren’t so simple; a third issue has been premier in voter’s minds over the last year, Immigration. The Most Trusted Party stats on Immigration currently hold at a dismal 23% to 19%, (with 33% preferring others).

It’s for this reason that holding huge leads in public trust on core issues isn’t enough. What really matters is how that lead of trust in particular issues translates into a firm intention to vote, and the best way to measure this is to look at how the electorate rates the importance of each.

Below shows how voters have ranked the importance of issues facing the country over the last twelve months.

National Importance: “Which of the following do you think are the most important issues facing the country at this time?” (Up to three selected. V Axis shows % of voters).

Despite challenger parties being given more air time during the campaign to advocate their respective visions, the importance of the NHS has this week surged to an all-time high, with the Economy retaking poll position. The state of play looks very different to when the Economy was last back on top, however, with the issue of Health a distant 23% behind in April 2014, compared to just 5% now.

This narrowing appears to be good news for Labour, but this data also tells us that of the three most pressing issues facing the country, more voters are still set to weigh their options against who they trust with the Economy over anything else. Furthermore, whilst the two main parties appear to finally be making headway in aligning more voters to their core issues, it’s clear that this election won’t be the simple Economy vs. NHS battle that they want it to be. The question of Immigration, of which both parties are held in very low regard, will continue to be significant in spite of its relative decline during the start of the election campaign.

Regardless – commentators, activists, strategists and even the odd interested member of the general public are scouring the horizon for the first sign of which way the polls will break. I suggest that for the best insight into how the vote of undecideds will firm up in the next 20 days, we’ll need to be watching these figures.

At present, the Economy’s marginally greater salience, along with the Conservatives slightly better performance in the tertiary issue of Immigration over Labour, seems to suggest that we are heading for a small Tory win in the popular vote. This prediction requires that the Economy have a lead over the NHS bigger than the margin of error, which in polling terms is just 3%. If Labour continues to bridge this now minuscule gap between the two, everything could change.

Will the gap shrink or widen? You might argue that this question is just the tip of the iceberg in what is a very messy election. But with things so unprecedentedly tight between the top two contenders, this election may well be won by the tip of an iceberg.