It appears as one take, although I think it's actually several different scenes with a seamless transition.

To me it's one of the best scenes if not the best scene I've ever seen in a movie: from a small intense escape scene to a full battle, followed by a revelation that brings people to their knees. All shot basically first-person, with extremely complex action and emotion. Absolutely gutting.

The car chase scene mentioned above https://www.youtube.com/watch?v=pOyAXPn1V9k

I only watched this movie once, maybe 15 years ago, and that scene has stuck with me. Rewatching it brought tears to my eyes again after all these years. That was some of the best, gut-wrenching movies ever made.

Not single-continuous takes:

> However, the commonly reported statement that the action scenes are continuous shots[53] is not entirely true. Visual effects supervisor Frazer Churchill explains that the effects team had to "combine several takes to create impossibly long shots", where their job was to "create the illusion of a continuous camera move". Once the team was able to create a "seamless blend", they would move on to the next shot. These techniques were important for three continuous shots: the coffee shop explosion in the opening shot, the car ambush, and the battlefield scene. The coffee shop scene was composed of "two different takes shot over two consecutive days"; the car ambush was shot in "six sections and at four different locations over one week and required five seamless digital transitions"; and the battlefield scene "was captured in five separate takes over two locations".

* https://en.wikipedia.org/wiki/Children_of_Men#Single-shot_se...