The monthly ComRes telephone poll for the Independent is out tonight and has topline figures of CON 32% (nc), LAB 33%(-4), LDEM 9%(nc), UKIP 14%(+4). The one point Labour lead is the lowest ComRes have shown in their phone polls since January 2012, and its the lowest level of Labour support they’ve shown since the government’s honeymoon in the summer of 2010. Meanwhile the Sun politics team have tweeted the daily YouGov poll. That too shows the Labour lead down, in this case to two points: CON 35%, LAB 37%, LD 9%, UKIP 13%. That’s the lowest YouGov lead since December.

As ever, unusual results demand particular caution. Sure, it could be the sign of a narrowing of Labour’s lead, but just as likely it could the random variation that affects all polls. There is a temptation to assume that a movement in the polls after an event – in this case Labour’s 50p tax pledge – is a response to that effect. Labour announce a policy, the next few polls show their lead collapsing – cause and effect. I would urge restraint. At first glance this looks like an obvious and appealing narrative, but it’s a human weakness to look for patterns of this type even when they aren’t there.

Firstly, while ComRes and YouGov happened to both be published at 10pm and show a similar pattern, they aren’t the only polls published today. Populus’s Monday poll was also conducted after the 50p pledge, at roughly the same time as ComRes, and they show Labour’s lead still at seven points. Even without that, we know polls jump about from day to day, YouGov have already shown a couple of 3 point leads this month that turned out to just be normal sample variation.

Equally initial polling showed that the 50p pledge was popular. Now, the reality is rather more complicated than that – a popular policy may play to a party’s wider weaknesses, could risk making Labour look anti-business, or the consequential criticisms from business leaders could have damaged their support. Nevertheless, I’d be surprised if the announcement of a broadly popular policy had backfired that badly.

We’ll have more polls in the coming days – not least we’ll know if YouGov’s daily polls are really showing the lead dropping or if today’s is just a blip. Of course, it could be that other polling does echo these findings and we do conclude that the 50p pledge went horribly wrong, it could be these are just part of a more gentle decline in Labour’s lead that has no link to the 50p pledge at all, it could be that tomorrow’s polls show things back to normal and today was merely a couple of freak results. Wait a couple of days before making a fuss about what could just be a co-incidence.