While it’s difficult comparing across polling firms and stripping out other effects going on, the best guess is that the gain for Others came from a net four point drop for the Tories and a seven point loss for Labour. Those movements in voter intention now look to have almost entirely unwound; yesterday’s Mori and YouGov polls giving further evidence of that. Others are still polling a little above the 10% they were usually recording a year ago – especially with Angus Reid, though there’s no comparable early 2009 data for them – but the voters the two big parties lost look to have mostly returned ‘home’.

That, however, leaves Labour with a problem if they’re to stop the Tories forming the next government or even prevent them winning a majority because a 30% share is really not enough if the Tories are on around 40%, and having regained what they briefly lost to Others, the remainder looks like a much tougher nut to crack.

Friday’s Angus Reid poll included a subsidiary question to respondents who indicated a voting intention of UKIP, Green or BNP, asking how they would vote if there wasn’t a candidate of their preferred party standing in their constituency.

Just 4% nominated Labour against 13% for the Tories and 16% for the Lib Dems. Fully 65% were unsure, would not vote or would vote for a different (unspecified) minor party.

Those are pretty measly numbers for the big boys (and especially Labour) and would indicate a strong anti-politics or anti-establishment feeling among the remaining UKIP, Green and BNP voters (Plaid and the SNP are a different case but there are few Con/Lab marginals where Plaid or the SNP will be significant players). If Labour runs a strongly negative campaign, it’s difficult to see those voters being attracted back into the red corner – and negative politics seems to be Brown’s style.

Of course, what really matters is not so much the Labour share as the gap between the Conservatives and Labour. If Brown’s team knocks a few points of the Tory score, even if it goes elsewhere, it will benefit them – though it would be a pretty inefficient way of doing it. That’s academic though unless they can do it, and apart from during a media shutout as during the Labour and Lib Dem conferences, Cameron’s Tories have been pretty invulnerable to those sort of attacks. It’s been self-inflicted wounds like expenses or Lisbon that have caused the longer dips in the Tory ratings.

So is it all over bar the voting? Not yet. During Brown Bounce II (the Banking Bailout), Labour took vote share from both the Tories and Lib Dems. If they’re going to get consistently beyond 30%, they’ll have to do so again.

In fact, in yesterday’s Mori poll, that’s exactly what happened (YouGov had a Tory decline rather than a Labour advance).  Why that happed is crucial: was it a deep-seated switch or a short-term reaction to (for example) the release of an economic statistic?  If the latter, Labour’s best hopes still rest on Cameron, Clegg or their respective teams going quiet or shooting themselves in the foot.

David Herdson