A thick and heavy tumbler in amethyst / aubergine pressed glass, the flared sides having a broad plain rim above a chunky hobnail pattern; 4 inches tall.
(Permission for the re-use of these images on the GMB granted by wight-boy33).
The base bears the registry date lozenge for 7 June 1883 – Parcel 20 (though the date letter is indistinct, so the lozenge reads ? – K – M – 20). The only design registration for that date was RD 399063, and the registrant was J. Defries & Sons, London.
The base is also marked ½ P (presumably ½ pint capacity) and DEPOSE (the French term for registered). Although Derfries was the design registrant, the DEPOSE mark on the base might seem to point to a French manufacturer.
This appears to be the final Defries family glass design registration (see my reply #11 above).
The online design registration summary from The National Archives does not give a subject, so it seems rather out of the Defries run of registrations to have a coloured tableware piece rather than a lighting-related registration, though Jonas Defries & sons is known to have supplied coloured lantern glasses for the Indian trade (also in my rely #11).
If Paul S. happens by this post, I wonder if he might have the design representation to RD 399063 to hand in confirmation of the registration details, please?