[1] RAF Flight Lieutenant Eric Williams was the navigator of a 75 Squadron Short Stirling bomber (BK620) shot down on a bombing raid over Germany on 17/18 December 1942.

(Peter Tunstall and Dominic Bruce claim to have used a wooden horse to camouflage a tunnel opening in the Spangenberg concentration camp two years previously, in 1941).

[2] With the assistance of a third POW, Oliver Philpot, the tunnel was completed by 29 October 1943 – an important factor, since Williams, Codner and Philpot planned to use the local railway to quickly put distance between themselves and the camp, rather than the usual escape strategy at the time of travelling on foot at night and hiding in barns or haystacks during the day, but the Escape Committee only had local railway timetables valid until the end of October.

[4] At the end of the war, on the long sea voyage home on the RMS Queen Mary, Williams wrote Goon In The Block, a short book based on his experiences.

[5] He included many details omitted in his previous book, but changed his name to "Peter Howard", Michael Codner to "John Clinton" and Oliver Philpot to "Philip Rowe".