It couldn’t be closer, and the figures are:

Theresa May: 22.7 per cent.

Boris Johnson: 22.6 per cent.

Michael Gove: 17 per cent.

David Davis: 11 per cent.

William Hague: 10 per cent.

George Osborne: 7 per cent.

Philip Hammond: 5 per cent.

Owen Paterson: 4 per cent.

Boris’s rating hasn’t fallen: he scored 22 per cent last month.  Nor has Michael Gove’s: he won 17 per cent then, the same as this month.  Rather, the Home Secretary’s rating has risen by four points.

With the impending Romanian and Bulgarian entry to Britain gaining lots of publicity, and the immigration pledge looking hard to reach, this is rather surprising timing.

The best explanation is that May’s reputation as an effective, focused and no-nonsense Minister continues to grow among Party members.

The size of the sample may also help to explain the result.  The Christmas survey gained 800 replies from Party members, up about 100 from last month.

We usually round the percentages up or down, but since Boris and May are on the same one, and readers will ask which scored higher, it’s sensible to publish the answer.

Choosing names to test will always be an art rather than a science.  Adam Afriyie was scarcely troubling the scorers, so we’re trying out Philip Hammond and Owen Paterson, who are possible contenders.

Neither of them rate much better first time out.  Nor does the George Osborne.  Despite the growing recovery, his score languishes on five per cent – down two points from last month.