As I wrote last month, our next Party leader survey has been through three phases since last May’s general election.

First, George Osborne got well in front – scooping over 30 per cent of the vote last September and holding his lead for the next three months.

Next, after the Chancellor’s tax credits clash and climbdown, and during the run-up to David Cameron’s EU renegotiation, Osborne’s rating fell as 2015 drew towards its close, while those of senior Conservatives known or believed to be sympathetic to Brexit rose.

Finally, as 2016 opened, Theresa May went top of the survey in January, Liam Fox replaced her in February (though with the joint lowest frontrunner share on record) and, last month, Boris Johnson powered his way to first place in the wake of his declaration for Brexit. With three different frontrunners in three months, after long spells of consistency both pre and post-election, the survey was clearly in flux.

And it still is. This month, we have a new frontrunner in our adjusted survey:

Michael Gove’s rating is up six points to 26 per cent, having risen by 12 points last month, when he reached 20 per cent. He tops the poll.

Boris Johnson’s score falls by 13 points, taking him to 20 per cent. Last month, his total of 33 per cent represented a rise of 14 points. He is second.

Liam Fox’s rating falls by 2 points, leaving him on 16 per cent. He is third. The words of YouGov’s Stephan Shakespeare on its own future Conservative leader poll, which I quoted last month, remain to the point in relation to the survey as a whole: “Support is strongly correlated with opinions about Brexit”.

I wrote in February that we would sooner or later make changes to the list of runners and riders, but am naturally very cautious about doing so. We believe that the time is right to put Priti Patel in the survey, and she has duly taken 9 per cent of the vote, which is not a bad total at all for a first outing.

The changes in the scores of the pro-Remain Cabinet members named are so small as to be margin-of-error stuff. Theresa May is up a point at 11 per cent, George Osborne down two at 9 per cent, Sajid Javid up two at 7 per cent, and Jeremy Hunt and Nicky Morgan bring up the rear.

So what is going on?

One possibility is that the result reflects a lower response rate, or a different group of respondents replying, or both. But the problem with this line of thinking is that the returns on other questions are very consistent – a point I made writing on Sunday about this month’s Groundhog Day result on our regular EU referendum question.

Another is that last month some respondents backed Boris in haste, enthused by him coming out for Brexit but, after clocking his performances on Marr and in front of the Treasury Select Committee, have been quietly repenting at leisure. These outings were not at all bad in my view, but they were characteristically, well, Borisian – and, as we know, his act tends to goes down better with the politically unengaged than the committed. Matthew Parris’s venomous attack on the Mayor may also have drawn blood: we have offered a qualified defence .

A further factor may be that the more party activists think about Gove’s early declaration for Brexit, the more they like it. He was top of our Cabinet League table last month. And they have shown a lot of support this month for this site’s recommendation that the Justice Secretary be appointed Deputy Prime Minister: some two in three of them backed it.

Finally, the poll result has been slightly adjusted because we are aware that supporters of one of the people named in the question are being encouraged to support of that person. The votes that come in as a result would obviously distort the result if counted, so we are not counting them. I don’t want to write more at the moment about what we know and how. The change to the total of the candidate in question is relatively small – a subtraction of about three per cent from the score in question.