It’s electroplate, made by the Sheffield company William Hutton & Sons. The last 2 symbols in the mark are gothic-style letters, B P, which stand for Britannia Plate. Britannia metal is a pewter-like base metal alloy.
As the surface is silver it should polish up nicely with silver polish - not junk, but not very valuable.
Phil
Thanks you very much! We have been sorting through my dads stuff trying to decide what to do with it. Maybe this one is for ebay in thay case!