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London Assay Office: hallmarks, history, and town mark

Oldest assay office in continuous operation in the UK. Established under royal charter 1300. The leopard's head is among the oldest hallmarks in continuous use globally.

Published May 30, 2026

Quick facts

Operator
The Goldsmiths' Company
Location
London, United Kingdom
Founded
1300
Status
Active
Town mark
Leopard's head (crowned 1478-1821, uncrowned thereafter)

About the London Assay Office

Oldest assay office in continuous operation in the UK. Established under royal charter 1300. The leopard's head is among the oldest hallmarks in continuous use globally.

The town mark

The London Assay Office strikes a distinctive symbol — Leopard's head (crowned 1478-1821, uncrowned thereafter). This town mark identifies where a piece was assayed, so spotting it on a ring, chain, or piece of silverware tells you which office tested and guaranteed its metal content.

Visit / official record

Goldsmiths' Hall, Foster Lane, London EC2V 6BN

Official site: https://www.assayofficelondon.co.uk/

Sources

* Frequently asked

FAQ

Q. Where is the London Assay Office?
A. It is based in London, United Kingdom — Goldsmiths' Hall, Foster Lane, London EC2V 6BN. It is run by The Goldsmiths' Company.
Q. Is the London Assay Office still operating?
A. Yes. The London Assay Office, founded in 1300, is still assaying and hallmarking precious metal today.
Q. What hallmark symbol does the London Assay Office use?
A. Its town mark is leopard's head (crowned 1478-1821, uncrowned thereafter). That symbol identifies the office where a piece was tested for purity, so you can use it to trace where the item was assayed.

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