Metals are tested and, if they meet a certain minimal purity requirement, are marked with a specified seal.

In the United Kingdom, this is done by the assay offices in London, Birmingham, Sheffield, and Edinburgh.

The act made business transactions involving unmarked metals illegal.

Another notable consequence of the act was the formation of the British Hallmarking Council (BHC).

The council was responsible for clearing up ambiguous statements in the regulations and for extending its definition to deal with other problems in the hallmarking law.