From Magicpedia, courtesy of Genii magazine:

David De-Val (1938-2002) was an escape artist an magician from the United Kingdom. De-Val started magic at the age of thirteen, inspired by a next door neighbor who used to perform magic tricks. While magic was a hobby, he worked as a mechanic in mills and later as a production manager for a pharmaceutical company. After seeing Paramount film "Houdini" at the age of fifteen, he started performing escapes at local carnivals and in the Oldham pubs. His first outdoor underwater escape was at a local gala in 1958 at the age of 20. He became a cabaret magician, performing many magical acts, including a "Dove Act" from 1960 to 1974. His career progressed to becoming a manufacturer of magical props. His first effect, "The Z Ray' Act", was marketed by Supreme Magic in 1958, a double act which he performed with Frank Koval. He made a television appearance on the UK quiz programme "Double Your Money" performing the "Dagger Chest” in 1962. He later appeared in the BBC TV "Hotline" which aired on September 26, 1984 where he Escaped from the Iron mask, Thumb Screw, and Handcuffs, while riding the Blackpool Pleasure Beach Rollercoaster at 60mph. De-Val spent many years researching various topics, including Houdini’s cell escapes