Yesterday, Pollwatch looked at the state of the parties in March; today it’s the turn of the party leaders.

As with all polls, what follows comes with caveats. Only three polling companies – YouGov, Angus RS and Mori – this past month asked questions specifically to find out the public’s views of the three main party leaders. And each asks variants on the basic question – do you think Clegg/Brown/Cameron are doing a good job – to come up with their figures, so comparison ain’t easy. But, still, we don’t indulge in polls often, so here goes …

Here, in chronological order, are the results of the four polls published in March asking the public to rate the three major party leaders:

Cameron: 46.0 approve, 40.0 disapprove: net +6%
Brown: 30.0, 60.0, -30%
Clegg: 45.0, 25.0, +20%
(17th March, Angus RS: Do you approve or disapprove of X’s performance as Y?)

Cameron: 49.0 well, 39.0 badly, net +10%
Brown: 33.0, 61.0, -28%
Clegg: 47.0, 27.0, +20%
(21st, YouGov: Do you think (name) is doing well or badly as (position)?)

Cameron: 42.0 satisfied, 42.0 dissatisfied, net 0%
Brown: 34.0, 60.0, -24%
Clegg: 44.0, 27.0, +17%
(24th, Mori: Are you satisfied or dissatisfied with the way X is doing his job as Y?

Cameron: 46.3 well, 41.3 badly, net +10%
Brown: 33.3, 60.3, -30
Clegg: 45.0, 27.0, +18%
(24th, YouGov: Do you think (name) is doing well or badly as (position)?)

Which gives us an average net popularity – and, yes, I know how unscientific such averages are – compared with February’s as follows:

Nick Clegg +18% (+4%), Gordon Brown -27% (-3%), David Cameron +5% (-4%)

Nick Clegg continiues to maintain his lead, therefore, as the most popular of the three main party leaders, with an average net rating of +18%, with all of this month’s four polls showing Nick ahead of David Cameron. It appears c.70% of the public have so far formed a view of Nick, and so far they are continuing to break roughly 2:1 in his favour.

The real big test, though, will be this month’s election campaign, and especially the three televised leaders’ debates, when Nick’s exposure will be the greatest of his time as leader. Generally Lib Dem leaders have become both better known and better liked during their first election campaign. A good performance from Nick should see the trend continue. But one gaffe, and who knows.

David Cameron’s ratings continue to dip. It was only in November that Mori was showing Mr Cameron with net +13% rating; by March, just as many voters were dissatisfied with his performance as were satisfied by it. It’s very hard to judge whether Tory ratings have fallen in line with Mr Cameron’s growing unpopularity; or whether he’s been dragged down by association with the still-contaminated Tory brand. The result, though, is the same: the Tories have a mountain to climb, as does Mr Cameron as leader.

If the Tories fail to win a mandate on 6th May, there’s an interesting counterfactual for Tories to ponder: how would the Tories be faring if David Davis had bested Mr Cameron in the Tory leadership contest? Though I doubt he’d have scaled the heights of polling popularity that Dave did in his first two years, my guess is he would have built a far more robust Tory lead by now. If I were a Tory, I’d have been much more confident of Mr Davis’s ability to land punches on Gordon Brown.

For Gordon Brown, after February’s big ratings increase (up 7%), March sees something of a dip (down 3%). Though Mr Brown is no longer plumbing the depths he was in December (when his net average rating was at a dire -38%) -27% is scarcely a comfortable rating just days before he goes to the Palace to request a general election. Especially as a large part of the result of this election campaign may depend on whether the public can stomach the thought of another five years of Gordon Brown as Prime Minister. If their answer is no, this next month will be Mr Brown’s last in the top flight of politics.