This Irish drama documentary feels like a contribution to ongoing efforts to guilt-trip the National Gallery in London into returning to Ireland more than three dozen French impressionist masterpieces bequeathed by the Irish art dealer Hugh Lane. When he wrote his will in 1913, stung by the Dublin authorities’ refusal to grant him planning permission to build a modern art gallery in the city, Lane left the 39 paintings to London. Later, he changed his mind, adding a codicil to his will. His intentions were as clear as day, but the codicil was unwitnessed. So, when he died aged 40 – travelling on the Lusitania, which was sunk by a German U-boat in 1915 – London got the paintings.

The film opens with a bit of context, setting the mood in Ireland at the turn of the 1900s. This was the era of Irish cultural revival, WB Yeats and JM Synge, of Irish trade unionism and nationalism. The dramatised bits work pretty well. Tom Vaughan-Lawlor is terrific as Lane, an Irish Protestant, the self-made son of a clergyman. When he stares transfixed at a Titian, there is a blazing chemistry between man and painting. No other relationship can compete. In fact, Lane’s eye was so good that if he so much as looked at a painting before an auction its value shot up.

Lane was a snob, but he believed in art for the people. His free-entry gallery in Dublin would have had a bridge over the Liffey, so that ordinary Dubliners would pass the Manets on their way to work. (“You may as well give strawberries to donkeys,” sneered a friend). The National Gallery in London asserts its strict legal rights over the painting, but Citizen Lane puts a convincing case that the moral right belongs to Dublin. (Too late for inclusion in the film, London and Dublin earlier this year reached a truce, agreeing to rotate a number of the paintings.)

• Citizen Lane is released on 12 April on digital platforms.