It’s arguable whether Wednesday night’s documentary on the history of the Irish border is the week’s

most important programme – although I would argue it is. What is not up for debate, however, is that it presents us with the week’s grandest opening.

Specifically, it offers the magnificent sight of Paddy Gillespie, a gentleman of Strabane, bombing down a busy highway on his electric bicycle, unencumbered by a helmet.

A man riding a motorised bike is not, you might say, such an unusual spectacle. But here’s the kicker: Mr Gillespie is 102 years of age. Older than the border itself.

The meandering dividing line that cuts across nearly 300 miles of rural farmland has existed since 1922.

From the first, it has been a source of turmoil, confusion, contradiction, anger and absurdity, best summed up by the exasperated comment of another contributor, journalist Fintan O’Toole: “I get fed up when people keep talking about ‘The Irish Border’ – it’s a British border!”

Now, of course, as Brexit staggers on, it is the source of a whole new tension. Which is, of course, only all the old tensions bubbling up again.

Short but sweet and achingly sad, this terrific film draws from almost 100 years of archive footage shot by documentary and news crews attempting to understand the nature of the border, and the fault line it represents. Meanwhile come new interviews with people whose lives have been affected by it.

Among them is John, who served there as a member of the British Army, and has been in a wheelchair since being shot in the spine on an operation in 1981 during which his colleague was killed. “The border is inside me,” he says.

It begins, though, like a comedy, as people discuss the various smuggling traditions that instantly flourished around the border, stories of the little guy beating the system that have the sly air of a Whisky Galore. Paddy Gillespie remembers swimming the river with illicit cows.

Ardal O’Hanlon recalls men getting paid for driving the same load of pigs back and forth again and again. Fintan O’Toole describes returning to Dublin from Belfast feeling like a Michelin Man, because of all the layers of smuggled new clothes he wore under his coat.

Things get harder-edged, but remain absurd, as the film explores the subject of how any infrastructure erected along the border becomes a magnet for trouble – we see Sisyphean footage of authorities labouring to block off roads and bridges, only to find all their work destroyed the next day, the paths open again.

From here it is into real horror. This

film is not a history of The Troubles, but

it is bluntly eloquent about illustrating them, and the atrocities come evenly balanced.

We hear the story of the horrendous 1975 massacre of the Miami Showband by the UVF; and we hear about the murder of Patsy Gillespie, who was kidnapped from his home by the IRA in 1990, and, while his family was held hostage, chained into a van loaded with a massive bomb and ordered to drive it into a checkpoint.

Lastly, we hear about the unlikely, hard-won friendship that has grown between his widow, Kathleen, and Anne Walker, a former IRA member.

It’s an unassuming little film, but tough, clever, pointed, human and – to employ a recently much abused word – meaningful. From a 102-year-old man to a wounded ex-soldier, from comedians to journalists

to farmers, from ex-IRA woman to widow, the voices are diverse. But all speak as

one to say a hard border must not exist again.