After the outbreak of World War II the Soviet Union occupied Lwów, murdered Knapp's father and sent Stefan to a gulag in Siberia.

[2] There, among other things, he worked building schools for Russian children who had been orphaned because their parents had been imprisoned or murdered for political reasons.

[3] While in the Gulag, because artistic endeavors were limited, he made chess sets out of bread and playing cards out of trash for his fellow prisoners.

[4] After the end of the war he remained in London and took advantage of a veteran's stipend to further his studies at the Royal Academy and at the Slade School of Fine Art.

There he presented a unique and innovative style and technique, which involved melting glass into pieces of light steel, using specially made furnaces.

In the early 1950s he painted a mural in the foyer of Hallfield Primary School, Westminster which was designed by the architect Denys Lasdun.

Knapp was the only Pole ever to receive the Churchill Fellowship, which he used to study and expand his knowledge of murals in Guatemala, India, Iran, Japan and Mexico.

[4] A retrospective exhibition of some of Knapp's best known works is currently installed at the Mid Wales Arts Centre, Maesmawr, Caersws, Newtown SY17 5SB