Thank you . It does fit description . No hint of colors . My dock area seems to be a campsite producing stone tools, pottery sherd, melted lead all sorts of time span.For comparison, these are 'utility' mugs from the 1940s from various British potteries:
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They were made primarily fir military use in canteens and such between 1943-1951. There's a bunch of them here being used by NAAFI workers to serve tea after a street was bombed during the war:
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