John Tams & Son Ltd mark: TAMS WARE Patent John Tams Ltd Stoke-on-Trent Made in England

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1875–1890

Crown Pottery JT

Registration number 89660 dates the Mikado pattern registration to 1887.

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c. 1875–1903

Crown Pottery J. T. Longton Warranted

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c. 1903–1912

Crown Pottery JT&S

Registration number 524969 dates the pattern registration to 1908.

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c. 1905–1912

John Tams & Son Earthenware Manufrs Longton Hop & Barley Rd No 463577

Registration number 463577 dates the Hop & Barley pattern to 1905.

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From 1912

EST 1774 Crown Pottery John Tams LTD Made in England

The source says this style continued into the 1960s; EST 1774 does not date John Tams’s business.

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From 1912

EST 1774 John Tams LTD Crown Pottery LONGTON PATENT

The source assigns this form to 1912 onward; Longton is the factory town.