Extinction Rebellion are on the rise and here to stay

Extinction Rebellion (XR) activists have been called all sorts of things.

Depending on who you speak to, they are earth warriors and selfless rebels. To others they are louts, agitators, and according to Boris Johnson, "uncooperative crusties".

But I think the names they've been given aren't as interesting as the way they see themselves.

High-profile activist Roman Paluch-Machnik told us during an interview: "For all this crisis situation, there is a clear pathway to how we should be dealing with it, which is nonviolent civil disobedience.

"It has historical precedent... people like Gandhi, Martin Luther King and Nelson Mandela who paved the way for what we're trying to do."

This was a revealing moment.

With the invocation of those icons, Mr Paluch-Machnik revealed how XR thinks of itself - an extension of a grand tradition of civil and human rights activism that has, to quote MLK himself, bent the arc of the moral universe towards justice.

Sky News has spent quite a bit of time filming with XR - an occasionally comedically chaotic organisation - and I think when people watch our special programme at 6.30pm tonight, they may find comparisons with Gandhi a bit of a stretch.

However, it is helpful as we seek to understand a group of people determined to alter the course of history, and with it the way we all live our lives, because it tells us a bit about how they relate to the rest of the world.

And what I see in many of XR is similar to what I've observed in radical left anti-fascist groups in America. There's the same sense of moral obligation, of believing there is no choice but to fight, and of feeling compelled to tackle an existential threat in the absence of government action.

To believers, this involves sacrifice, risk, and submission to a cause they believe is greater than themselves.

But there are uglier traits too - the same zealousness, the same righteousness, the same absolutism or even fundamentalism - and in some cases arrogance and entitlement.

Because wherever you stand on their cause, this group of unelected citizens has decided to take matters into its own hands. They have decided that shutting down major cities and breaking the law is worth the inconvenience and disruption it causes, and that asking nicely for change is no longer an option.

They fervently believe they are acting to save our planet.

Many are with them - they have have attracted a surprising range of supporters.

But many are not - as the angry scenes at Canning Town tube station showed.

Whether they succeed or fail in bringing the people with them, if we view XR the way it views itself, we should all understand that they are not going away.

Their brand of radical resistance is on the rise, and it's here to stay.

Sky News will broadcast Inside The Rebellion - an intimate portrait of the climate protests that crippled London - at 6:30pm tonight