Thank you for your excellent photos - very clear, and helpful.
You have obviously seen the mark, and recognised the maker as Hammersley & Co, a long-established and well-respected manufacturer based in Longton, one of the six towns that comprise Stoke-on-Trent. Although founded as a company in 1885, the history of Hammersley goes back further, and has links with Stoke since the 1860s. The name was changed to Hammersley and Co (Longton) Limited in 1932, when the acorn logo was introduced, and finally to Hammersley China in 1974, when it was taken over by The Porcelain and Fine China Companies Limited, owners of Royal Worcester and Spode. Palissy Pottery Ltd, also part of the group, continued to use the Hammersley name until 1989, when it was sold to Aynsley China. They in turn were bought out by Belleek in 1997, and the factory in Stoke closed, ending an association lasting over 150 years. The Hammersley backstamp hasn't been used since 1989.
The mark on your cups is much earlier than the one on the upturned bowl (?), as revealed by the font used for the word "Victorian". The one on the underside of the cups is noticeably different, not only in the way the "Victorian" type is used, but also by the presence of the earlier crown in the middle of the stamp. This means your cups date from between 1939 and around 1950, but the other piece is from after 1974. I assume the mark on the saucers is the same as the cups, as the later mark appears to be on a small bowl?
The "Victorian" pattern is an underglaze transfer design, and was available in cobalt blue (as your cups and saucers), a bright magenta rose colour, a sepia orange, and a dark sage green. Although called "Victorian", the design was introduced in the 1920s, and seems to have remained in production for about 20 years.
Of the various colour-ways, the blue is the most common, with the pink and the green the rarest. However, the blue still has the greater appeal, and is collected not only by those who appreciate Hammersley china, but also collectors of Blue & White. I have been able to find several instances of Victorian pattern being sold recently. A full service of 42 pieces, including 12 cups and saucers like yours, with sugar bowl, creamer and sandwich plate (but missing the pot) sold at auction for £92 plus fees (total £110), but this is typical of saleroom figures, where larger lots go to the trade and rarely realise their full potential.
A more realistic estimate will come from looking at genuine sales figures for individual cups and saucers. There are keen collectors for singletons, and sold individually, examples of Hammersley "Victorian" can fetch £15 - £18 each. In truth, tea cups do fetch more, and can realise £30, but coffee cups like yours are still desirable.
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