This Act introduced milled coins (which cannot be "clipped"), and raised the standard of wrought plate from the sterling standard of 92.5% purity to 95.8% pure silver. New hallmarks were ordered with the new standard being marked with a Lion's Head Erased (torn off at the neck) and a figure of a woman "commonly called Britannia" which replaced the Lion Passant and the Leopard's Head Crowned.
In addition, makers were required to register new marks using the first two letters of their surname instead of the usual practice of the initials of the forename and surname, a single initial or a device.

The new standard was obligatory throughout the Kingdom but it was in 1700 that the Assay Offices of Chester, York, Exeter and Norwich were brought in to line. The Newcastle office followed in 1701. Scotland was not at that time under the jurisdiction of Westminster.

Although the new standard lent itself to finer work, it was softer and was not as robust as the sterling standard. It was also more expensive. Many makers immediately began to lobby for the reinstatement of the sterling standard but some, notably many Huguenot-born silversmiths who were used to the higher standard in France and those in the export trade counter-petitioned for it's retention.

 On the 1st of June 1720 a compromise was reached, the Sterling standard was restored (but with the imposition of a 6d per ounce duty on all wrought plate) (see: Duty Mark) but those who preferred working in the Britannia Standard were still allowed to use the marks of Britannia and Lion's Head Erased.