A new Colmar Brunton poll for TVNZ conducted in one of National’s bleakest weeks makes tough reading both for the party and its leader.

As is often pointed out, to read too much into any one poll is folly: it’s the patterns that matter. That’s a fair point; some of us do every now and then get over-excited by the increasingly rare polls dropped into the public domain. But a single poll can mean a lot if it affects the mood of politicians themselves. Just look at Australia, where the rat-a-tat weekly polling can determine the fate of a prime minister. If a poll dip is enough to prompt just a few important members of caucus to question their own job prospects, and lose faith in the leader, that one poll really does matter.

Could the latest Colmar Brunton poll for TVNZ, which has just been revealed by political editor Jessica Mutch McKay, be one of those? However much the Jami-Lee Ross saga and the sight of an imploding National Party can be pinned on Simon Bridges personally – and at this stage it’s hard to see how much of it is his fault – the real threat to his leadership is as a lower bucket on the fountain, beneath an opinion poll like this, which puts Labour above National in the tussle of the two major parties.

The headline poll numbers:

Labour: 45% (up 3%)

National: 43% (down 2%)

Green Party: 7% (up 1%)

New Zealand First: 5% (no change)

That’s not good, but neither is it catastrophic. Put another way, the parties of government have 55%, and opposition parties – well, there’s only one of them in this poll, as ACT doesn’t even register the 1% the Māori Party chalked up. If ever there was a time for voters on the right to jump to David Seymour’s party, surely this would be it.

The preferred PM numbers for Bridges, however, aren’t a lot of fun. Jacinda Ardern goes up to 42%, a country mile ahead of Bridges, who has dropped three points since the last Colmar Brunton poll for TVNZ, to 7%. Winston Peters has fallen away a little to 4%. But – doomy piano chords – Judith Collins is right behind Bridges, in third, on 5%.

Gulp.

And almost four in 10 polled thought less of Bridges over his management of the Jami-Lee Ross debacle, even if he told One News “I think I’ve done the right thing at every step of this”.

Given all of that, Bridges came across as surprisingly sanguine on the TVNZ item. There was “no sugar coating it”, he said, with the look of a man sipping a beer after swimming to shore from a shipwreck. “Last week was the toughest, worst week in politics I’ve seen for National and I think for any leader”.

Maybe he feels a little liberated. Maybe he’s confident the worst is over. Maybe he’s awash with relief that the drop in party support is so modest, after such a dreadful week. Maybe he’s just decided to stop worrying.

Today he ordered an internal inquiry into National’s culture over the way women are treated in the party, so that’s a necessary step – especially if it takes a wider view of the tactical approaches, responses to harassment allegations, and approach to mental health issues.

But maybe he also thinks – or hopes – that the worst is over. That the only way from here is up. It certainly feels an unlikely moment for anyone in caucus to challenge Bridges. Chances are there will be loyalty and solidarity for at least the next month.

The next poll could be the one. If the next poll doesn’t show things looking up, even a little, for Bridges and the National Party, then that could be the straw that breaks the caucus’s backs.