I haven't directly read these instructions myself, but I do like this quote from "Most Secret War" by R.V. Jones: they [the Royal Aircraft Establishment] had a

I haven't directly read these instructions myself, but I do like this quote from "Most Secret War" by R.V. Jones: they [the Royal Aircraft Establishment] had at one stage changed the method of packing bombs into crates, with the result that a crate arrived at Farnborough bearing the legend ‘Caution! The bombs in this crate are packed in a different manner from that formerly used. Compared with the old methods the bombs are now packed upside down, and the crate must therefore be opened at the bottom. To prevent confusion, the bottom has been labelled “Top”.’