Painter of landscapes, flowers and portraits, and art dealer. He studied with Bernard Meninsky at the Central School of Arts and Crafts. Showed very successfully with Redfern Gallery, which sent him to Spain, France and the Canary Islands to paint. Also exhibited at NEAC, Tooth and RBA. During World War II Jonzen was involved in camouflage, service including Norway and Nigeria, lecturing on it in Edinburgh. Married the sculptor Karin Jonzen, as she became known, their son being the artist Martin Jonzen. After the war they renovated Sir Hugh Lane’s studio house in London’s South Bolton Gardens and ran a Weekend Art Gallery there, which attracted many distinguished clients. Later, Basil Jonzen was involved in the St George’s Gallery. Arts Council holds his work.