GPO Poster: "pack parcels carefully"
Source: http://www.flickr.com.Image via Mikey Ashworth on Flickr. License: All Rights Reserved.
"A fine, bold design by Henrion as part of a common GPO theme of the time – packing parcels carefully. F H K Henrion was one fo the foremost of many German emigres of the 1930s who subsequently based themselves in the UK and did much to further the cause of design and commerical art." — Mikey Ashworth
If the stencil line is a typeface I don't know it.