It was built by Italian prisoners of war during World War II, who were housed on the previously uninhabited island while they constructed the Churchill Barriers to the east of Scapa Flow.
The chapel was constructed from limited materials by the prisoners. Two Nissen huts were joined end-to-end. The corrugated interior was then covered with plasterboard and the altar and altar rail were constructed from concrete left over from work on the barriers. Most of the interior decoration was done by Domenico Chiocchetti, a POW from Moena. He painted the sanctuary end of the chapel and fellow-prisoners decorated the entire interior. They created a front facade out of concrete, concealing the shape of the hut and making the building look like a church.