Among the works on show at the exhibition of German expressionists at the Holt festival, there are paintings by masters such as Klimt and Schiele. But one canvas among the masterpieces, a simple portrait by a little-known painter and academic being displayed for the first time, may stop visitors in their tracks – not for the deftness of the brushstrokes, or the vibrancy of the colours but for the deep gash across the neck of the subject. The 1920s painting of a Dutch woman in traditional costume is badly damaged, but its owners have no intention of repairing it before its first-ever forthcoming exhibition, and with good reason. The slit in the canvas tells a chilling story of escape from the Nazis in 1938. The scar was caused by German border guards boarding a train and slashing packing cases with their bayonets – checking for any escapers from Vienna. The oil painting was inside one of those cases. It was the year of the Anschluss, the annexation of Austria into the German Reich, which prompted a rise in violence and discrimination against its Jewish population. It was also the year that the first Jews and political prisoners were sent on a train from Vienna to their deaths in the Dachau concentration camp. The painting’s owner is Marianne Fry, the mother of the actor and broadcaster Stephen Fry, whose stepmother, Claire Grabscheid, was then a young Viennese lawyer who escaped with her parents to England. They paid the authorities to be allowed to bring some of their cherished possessions and the painting was among them. Stephen Fry discovered the deaths of his family members in the Holocaust when he appeared in the BBC series Who Do You Think You Are? He had long thought that his mother’s cousins had died at the hands of the Nazis, but actual documentary evidence of their fate affected him deeply: “Seeing their names there and that fucking word, Auschwitz, it does something to you.” The family have kept the painting in its damaged condition because it helps to tell the terrible story of the Anschluss in such a dramatic way. It is now being loaned to an exhibition on German expressionists and the Third Reich as part of the Holt festival in North Norfolk. James Glennie, its co-curator, told the Guardian: “The tear is a chilling reminder of what so many families went through.” He was aware of the painting because he has known the Fry family for several years. It was painted by a little-known artist, Yehudo Epstein, a professor at the Vienna Academy who emigrated to South Africa after the Nazi party’s rise to power. Measuring 24in by 30in, it was not a valuable painting in 1938, but the family had simply loved it. Glennie said: ‘This well-crafted painting of a Dutch girl by the fire in a rural kitchen with copperwares is not untypical of Epstein’s work, which included domestic Jewish interiors, figurative subjects, including nudes, as well as landscapes and cityscapes. He has included a religious reference with the crucifix on the wall behind the sitter, a motif he frequently employed in his works. “The disquieting slash through the sitter’s neck, which the Fry family have so discerningly chosen to keep, tells such an important story.” He added that, without the slash, it might have been worth about £1,500 today. “With the damage, it might be worth perhaps five to 10 times as much. In some ways, it became more precious because it got stabbed.” The Holt festival, which runs from 13 to 27 July, will explore Adolf Hitler’s purge on modernist culture of art, music and literature. In addition to works by the German expressionists, it will also include those by artists who were designated degenerate by the Third Reich. Entry to the exhibition and much of the programme is free.