The traditional stage is familiar from thousands of primary school Christmas celebrations. Mary kneeling by a manger, angels with haloes on sticks, a diminutive king with an outsized crown.

But behind the actors and audience loom the menacing concrete slabs of a vast barrier wall, and the spotlights of the stage are augmented by searchlights from a watchtower housing snipers and machine guns.

The sketch, published exclusively in the Observer, is part of the latest Palestinian territories project by Banksy, the anonymous but ubiquitous street artist who has spent more than a decade travelling to both the West Bank and Gaza to make art and occasionally stir up controversy.

This Christmas, he teamed up with the Oscar-winning director Danny Boyle and Palestinian Riham Isaac to stage a nativity play in the shadow of Bethlehem’s barrier wall, the type of playful but highly political art that has become his trademark. The one-off performance of an “alternativity”, with angels who send their tidings of joy through text message rather than personal visitations, was watched mostly by local families and journalists.

But a documentary about the project will run on BBC2 on Sunday evening, bringing a much larger audience for the play and the questions it raises about what the Christmas message of peace means in a region mired in conflict.

Banksy rarely talks about the motivation behind his work but the sketch of the stage and a series of other images shown here for the first time give some clues to his inspiration and the evolution of his artistic plans.

Evolution of Cherub Wall by Banksy in Bethlehem. Photograph: www.banksy.co.uk

One set shows how he planned a prominent new artwork for the wall. The first is just jottings on a photograph, showing his first thoughts on location and shape; then a pencil sketch on tracing paper gives a better sense of the design, two cherubs trying to prise apart concrete panels with a crowbar.

In the final piece, one angel hides its face behind a bandana, and the other wears a beanie. They floated just over the mock security gate that the audience had to pass through for the evening’s show, after the Palestinian co-director asked for Banksy to replace a looming Trump mural. In another black-and-white sketch, a shepherd stands outside his modest hut, gazing at a sprawling maze and the looming barrier wall that hides his destination, a small mosque. It is perhaps a nod to the many daily frustrations and humiliations of life in the Palestinian territories, where the wall is just the most obvious physical manifestation of the restrictions the residents face, which Boyle explores in the film.

In a third drawing, tourists stream out of buses into the nearby Church of the Nativity, turning their backs on the wall – and the Walled Off hotel Banksy opened beside it. A final map shows borders of Gaza and the West Bank replaced by barrier walls.

Banksy convinced Boyle to fly out to Bethlehem to direct the play, probably one of the smallest productions the Slumdog Millionaire director has worked on in decades.

The Bristol-born artist presumably hoped that the combination of his name, Boyle’s reputation and the unusual nativity show itself would attract the kind of viewers who would not normally settle down to an hour-long programme about the Israel-Palestine conflict on a Sunday evening.

Whatever his reasons for taking part, Boyle was an inspired choice. Engaging and honest about how little he knows about the region, he takes the viewer with him on an exploration of the restrictions and indignities of life in Bethlehem and other parts of the West Bank.

The documentary is also honest about Palestinian ambivalence towards Banksy, his hotel and his latest project, which stops it from feeling like part of the vast publicity machine that has turned the artist into a virtual industry.

At the start of their collaboration, Isaac warns Boyle that they may struggle to find actors, or even an audience, for the play. Palestinians find the barrier menacing and try to stay away, and parents worry about spending an evening near a wall whose very existence some have tried to hide from their younger children.

Just before the performance, Banksy left another Christmas message on a doorway nearby. “Peace on Earth”, with a Christmas star beside it, noting that “terms and conditions apply”.