The Guardians of the Standard of Wrought Plate is a body of 30 people created by an Act of Parliament in 1773 The Guardian's duties where primarily to choose four Wardens to oversee the daily running of the Sheffield Assay Office.
The Guardians were a diverse group of people from across religious, political and social barriers, some being business rivals and some related by blood and marriage, but all with a common uniting aim being a desire to set up an Assay Office so that the silver industry could expand in Sheffield. Originally all local people, the number of silversmiths on the body was limited to nine, to avoid them being able to exert any undue influence.
Many of the original Guardians were known to each other through their involvement in other concerns. For example The Town Trustees, The Company of Cutlers in Hallamshire, The Silver Platers' Trade Association and other related organisations.
Today, there are still 30 Guardians assisting the Assay Master, who meet twice a year in April and October. The Guardians advise on different areas of the business, providing valuable information relating to bullion, prices, law, trading standards, enforcement etc.
The current Sheffield Assay Office Guardians include:
| Mr Peter Broadbent | Non - Trade |
| Mr Duncan Campbell | Enforcement |
| Mr Richard Carr | Trade |
| Mr Guy Lightowler | Trade |
| Ms Helen Dimmick | Trade |
| Mr Nick Dodd | Non - Trade |
| Professor Roger Eccleston | Non - Trade |
| Mr James Frampton | Trade |
| Ms Emma Paragreen | Non - Trade |
| Mr Brett Payne | Trade |
| Mr Chris Heaton | Non - Trade |
| Canon Keith Farrow | Non - Trade |
| Mr Chris Knight | Trade |
| Ms Joanne Leach | Trade |
| Mr Suneel Babber | Trade |
| Mr Craig McKay | Non - Trade |
| Mr Corin Mellor | Trade |
| Mr John Mothersole | Non – Trade |
| Mr Lucas Rootman | No - Trade/ Enforcement |
| Mr Matthew Sibley | Enforcement |
| Mrs Kim Streets | Non - Trade |
| Ms Jackie Tear | Trade |
| Mr Charles Turner | Non - Trade |
| Professor Gill Valentine | Non - Trade |
| Ms Colette Bishop (Staff Guardian) | SAO Staff Rep |
| Ms Cheryl Foster (Staff Guardian) | SAO Staff Rep |
| Mr Ed Thomas | Non - Trade |
| Ms Vicky Clarke Brown | Non - Trade |
| Mrs Bookey Oshin | Non - Trade |
| Mr Howard Freeman | Non - Trade |
| Mr Christopher Brzozowski | Non - Trade |
| Executive Committee | |
| Mr Charles Turner (Chairman) | Non - Trade |
| Mr Chris Heaton | Non - Trade |
| Mrs Bookey Oshin | Non - Trade |
| Mr Matthew Sibley (Law Clerk) | Enforcement |
| Mr Ed Thomas | Non - Trade |
| Ms Jackie Tear | Trade |