Read the stamp
EPBM silver mark
With an EPBM silver mark, it can occur on teapots, jugs and other hollowware, usually with the manufacturer’s name and an item number.
Britannia metal beneath the silver
The BM part names the substrate rather than a silver purity grade. It can occur on teapots, jugs and other hollowware, usually with the manufacturer’s name and an item number. Britannia metal differs from the 958 Britannia silver standard.
What to check next
Compare EPBM with EPNS, which has a nickel-silver base. On a teapot, record both body and lid marks; a number may pair components or identify a shape rather than provide a date.