Bloody Sunday, 1920 (RTÉ One, 9.35pm) is an earnest if occasionally convoluted attempt to tell the story of that day of mass slaughter in Dublin. It is forensic in its narration of the events. And it chillingly evokes the horrors the match-goers must have felt as the Auxiliaries and Black and Tans opened fire at Croke Park.

The documentary, adapted from Michael Foley’s book The Bloody Field, begins with a chronicling of the assassination of the “Cairo Gang” of British intelligence officers by Michael Collins’s “Twelve Apostles”.

“They’ve been identified and noticed as fellas who did what they were told - they were good volunteers,” says Dr Anne Dolan of Trinity College, Dublin of the squad. “There’s a certain sense that younger men, late teenage years, their conscience hasn’t developed to the same degree that it may in the next 10 years and they may well be more prepared to do certain things than their older peers.”

“I put the two of them up against the wall,” says Vinny Byrne, one of the “Apostles”, in an archive interview. “I said, “the Lord have mercy on your souls”.

One issue is that the documentary makers seem to have interviewed every historian in Dublin and beyond. The talking heads bring often diverging perspectives.

Such an approach reflects the widely-accepted belief that commemorations of the War of Independence and the Civil War should strive for nuance and resist framing history in black and white. Yet squeezed into a 60 minute documentary it can make for overwhelming watching.

We move on to the shootings at Croke Park. The sheer weight of testimony again risks overpowering the viewer and it is worth asking whether the film might not have benefited from a longer running time (perhaps it should have aired over two evenings).