... there were many reasons for not marking British glass ...
Glen â€” Plagiarism by British glassworks is certainly not a reason for not marking British glass. Like the US glassworks, they seem to have enthusiastically copied foreign designs, presumably because litigation was unlikely, although we know of several examples of British glassworks copying each others' products.
Bernard mentioned US glass makers possibly copying UK glass makers.
I did not use the word "possibly", I stated it as a fact. Please disagree with me, or correct an error, but I would be grateful not to be misquoted, as I generally choose my words very carefully.
... they [Walsh] appear to have had an excellent understanding of the US market. I believe they accepted that the better of their designs would be copied, and that there was no way of protecting them. An example is Opaline Brocade, which was copied by Northwood within a year of its launch by Walsh. Incidentally it happened equally in the other direction, for example, the famous Edward Bolton "Grace Darling" boat is an almost exact copy of the Hobbs 101 Yacht Celery. This had a major impact on Walsh in that I believe it explains why so few of their registered designs were marked (almost an open invitation to copy), and also their marketing approach to the US, which appears to have been to send over a large shipment to their agents, and then start all over again with completely new designs. I can find no other obvious business reason for the constant and amazing innovative drive at the Walsh glassworks. ...
As you can see, Glen, I am even-handed when the debate warrants it.