Each month, the ConservativeHome survey of Party members features a topical question. Last month, we asked who was “most to blame for the dangers to party unity after the EU referendum ends”. Given that by the start of May it was clear that the referendum rough and tumble had only really begun, we decided to ask it again this month.

The first time we asked the question, 52 per cent of the 920 Party member respondents said that Cameron, Osborne and the Remain campaign were most to blame. They increased their strong lead in the blame stakes this month – after four more weeks of domineering campaigning by the Government and its allies in the IMF and so on, the numbers have grown: this time, 58.6 per cent blame them – an increase of 6.6 percentage points, presumably representing those disgruntled by the intensity of the pre-purdah barrage.

On the other side, the numbers blaming Boris Johnson, Michael Gove and the Leave campaign have reduced very slightly, falling from 16 per cent to 15.2 per cent. Similarly, the number sharing the blame equally between both teams rose from 11 per cent to 12.8 per cent.

The largest shift was seen in the fourth option, “There is no substantial danger to party unity after the EU referendum ends. The media is simply getting over-excited as usual.” (Or as we might now call it, the Dan Hannan option.) This group shrank by over seven points, from 20 per cent last month to 12.9 per cent this month. Or to put it another way, over a third of those who thought at the end of April that there was no danger have now changed their minds.

Whatever your personal view on which side should carry the can, that last result rings true for me: as the battle intensifies, and as some of those involved seem to reach for ever more vivid rhetoric, the ties of Party unity are indeed being strained. Whether it is a Remain vote or a Leave vote, Cameron will have to move swiftly but also carefully to ensure the Tory Humpty Dumpty stays firmly seated on top of the wall.