Coward joined the Army in June 1924 and was captured in May 1940 near Calais while serving with the 8th Reserve Regimental Royal Artillery as BQMS, Battery Quartermaster Sergeant.

Monowitz was under the direction of the industrial company IG Farben, who were building a Buna (synthetic rubber) and liquid fuel plant there.

Determined to do something about it, Coward used Red Cross supplies, particularly chocolate, to "buy" from the SS guards corpses of dead prisoners, including Belgian and French civilian forced labourers.

[7] He then gave the documents and clothes taken from the non-Jewish corpses to the Jewish escapees, who adopted these new identities and were then smuggled out of the camp altogether.

[7] In December 1944 Coward was sent back to the main camp of Stalag VIII-B at Lamsdorf (now Łambinowice, Poland) and in January 1945 the POWs were marched under guard to Bavaria, where they were eventually liberated.

On the back cover of the current edition, he is billed as "The Man who Broke into Auschwitz" (which is also the title of Denis Avey's book).

The film was lighthearted compared to the book and made only passing reference to Coward's time at Auschwitz; it concentrated instead on his numerous escapes and added a fictitious romantic liaison.

In 2003, Coward was further commemorated with the mounting of a blue plaque at his home at 133, Chichester Road, Edmonton, London, where he lived from 1945 until his death.