Any small party can be an odd place. Just ask UKIP, which has seen its share of would-be big fish splashing into the pond over the years, many of whom have later been savaged by Nigel Farage, its resident pike.

There’s always the risk that the smaller the party, the more potential there is for such inter-personal tension. That potential is increased when the party’s de fact leader and its official leader cease to be the same person – as we saw when Farage stepped aside only to continue hovering over the shoulder of Lord Pearson, his successor (whom he later succeeded).

The same seems to be happening to the Greens, albeit in the kind of passive-aggressive, kumbaya manner which one would expect of them. Natalie Bennett may officially be their leader but in practice Caroline Lucas is always there, and is still looked on as the actual figurehead. The Farage comparison continues when you consider who is the Greens’ most effective media performer – it certainly isn’t Bennett.

There’s a reason why effective ex-leaders in most parties normally keep a relatively low profile after they leave the job – if they’re constantly popping up it distracts from the new person. Worse, their presence can sharpen criticism when their successor messes up, as happened last week.

The difference for the Greens is that it is far from clear that Lucas intended her decision to leave the leadership as a permanent one. Her statement on stepping down was replete with references to how in touch with Green values her act was. Since then, far from entering a political retirement she’s continued to be at the forefront of their national presence. It’s not hard to imagine that she might be willing to accept the request of a grateful membership to return in the fairly near future. She even appears on the banners for their 2015 campaign, alongside Bennett – no doubt her party would say this is because they’re different from the others, and not all about leader-worship, but it looks more like a personality cult than not.

None of this makes Bennett’s job any easier – she may have the technical power of leader, but while the éminence grise (or rather, éminence verte) remains in the background she can never really have the full authority of the role. “Brain freeze” may strike from time to time, but at least at some point it goes away and lets you get on with the job.