The Britannia silver standard (95,84% of fine silver)(note 1), was introduced by a 1697 Parliament's Act signed by William III to replace sterling silver (92,5% of fine silver) as the mandatory standard for items of wrought plate. The decision was taken to limit the practice of clipping and melting sterling silver coinage (which standard was maintained to sterling) to make silverware. This behaviour had its origin during the reign of Charles II (after the "restoration"), owing to of the largely increased request of fashioned silver for luxury and ostentation purposes (note 2).
The change of the "standard" required the change of the hallmarks. The "lion passant guardant" denoting sterling standard was replaced with the female figure, commonly called "Britannia". The "leopard's head" mark of the Worshipful Company of Goldsmiths (identifying the London Assay Office, but used in many provincial offices together with their proper town mark) was replaced with a "lion's head erased" (note 3)
Moreover, any silversmith was required to register a new maker's mark composed by the first two letters of his surname (instead of the initials of forename and surname, single initial or a device previously used).
The "Britannia standard" alloy was softer, less robust and a little more expensive compared to "sterling standard". Many silversmiths immediately began to lobby for the reintroduction of the "sterling standard", but many Huguenot silversmiths who, because of their origin, were familiar with the higher standard used in France (95 % fine silver), petitioned for its retention. Furthermore, the maintaining of "Britannia standard" allowed the export of English silver to France (while this practice was not allowed with "sterling" silver which was below the standard authorized in France).
"Britannia standard", compulsory from 1697 to 1720, did not produce any significant effect, and the "sterling standard" on silverware production was restored on 1 June 1720 ((note 4).
The restoration of the "sterling standard" ensued in the adoption of former hallmarks used prior 1697 ("lion passant guardant" and "crowned leopard head"). However, "Britannia standard" was not abolished and remained in use also after 1720 as a voluntary alternative option to the "sterling standard". It was rarely used for making silverware after 1720 and usually only for high level reproduction of antique items.
After 1720 silversmiths maintained the use the their former maker's marks (initials) for works in "sterling" silver standard while the later system of hallmarking (first two letters of the surname) was used for works in "Britannia standard".
The practice of using two sets of marks continued until 1739. At this date, due to the confusion which had arisen, plate workers were ordered to destroy their existing marks and register a new one composed by the initials of their Christian name and surname, choosing letters of different character from those previously used (note 5).
The "Britannia standard" had a revival in the reproduction of antique items in the late Victorian Era (late 19th century), during the reigns of Edward VII and George V (first third of the 20th century) and in more recent years (1960's and 1970's).
After the hallmarking system change (1 January 1999) "Britannia" silver is marked with the millesimal fineness hallmark "958", associated, on an optional and voluntary basis, with the "Britannia" symbol.
The marks of "Britannia" and the "lion head erased" had only slight changes over time so that the dating of items manufactured using these standards depends especially on the "date letter" (representing the year in which the object was verified by the Assay Office) and on the maker's mark initials (modified in 1739, when new criteria were introduced).


IDENTIFYING BRITANNIA STANDARD HALLMARKS

Britannia standard silver is hallmarked with the "lion head erased" (which substituted the "crowned leopard head") and the "Britannia" (which substituted the "lion passant guardant")

Britannia, standard mark for silver fineness of 95,84 % (compulsory between 1687 and 1720)	Lion head erased, in use as London Mark for silver of Britannia standard

The spoons represent most of the items marked "Britannia" (1696 - 1720, when the use of Britannia standard was compulsory) actually available on the market. Other objects (mainly tankards, castors, mugs, loving cups and porringers) rarely are offered for sale.
The main problem met in dating these objects is the poor condition of their hallmarks, totally or partially rubbed as a result of three centuries of use combined with the softness of Britannia alloy. Furthermore some of the "court hand" letters (a style of handwriting formerly used in the English law courts) used in the cycles of dates of the period are very similar to each other and difficult to identify. In dating the spoons, some help can be found examining also their style pattern the evolution of which, over time, is quite well known.

London 1698 - Isaac Devenport

London 1700 - William Scarlett

London 1703 - John Smith

London 1706 - William Burridge

London 1713 - Henry Clarke

London 1719 - Andrew Archer

London 1719 - Samuel Hitchcock

London 1702 - Nathaniel Locke	London 1712 - Charles Adam

The maker marks can be useful when the date letter is rubbed:
- between 1697 and 1720 the maker mark was composed by the first two letters of his surname;
- between 1720 and 1739 the maker mark should be composed by the first two letters of his surname for items made in "Britannia standard" and by forename and surname initials for item made in "sterling silver";
- since 1739 until 1999 both "sterling silver"; and "Britannia standard" items were marked with the silversmith's forename and surname initials (or the forenames and surnames in case of association of silversmiths). In addition during the 19th and 20th centuries marks often referred to companies (…co or ..& co) and Limited (Ltd).

An example of a maker’s mark formed by the first two letters of the silversmith’s surname (L A), in use during the period of the Britannia standard (1696-1720) (Paul de Lamerie)	An example of a maker’s mark formed by the initials of the silversmith (P L), in use before and after the period of the Britannia standard for sterling silver (Paul de Lamerie)	London 1732 – Paul de Lamerie

Between 1784 and 1890 any items should be marked with the "sovereign head", denoting that payment of duty on wrought plate had been made to the Crown.
In addition commemorative optional hallmarks can also appear at the proper date (see "British and Irish commemorative hallmarks" article)

London 1935 – Elkington & Co. (with the optional George V silver jubilee commemorative hallmark)

After 1975 the "leopard head" was substituted for "lion head erased" and also for the "Britannia silver standard".
After 1999, when the millesimal system was adopted in UK, an oval with the number 958 or 999 is stamped together with the maker's mark and the Town mark, the "Britannia" and date letter being optional after this date.

London 2004

Between 1697 and 1720 the "Britannia standard" can be found struck on items hallmarked in London, but also in Chester, York, Exeter, Norwich and Newcastle. On these very rare items the "lion head erased" should be accompanied by the respective town marks of the proper provincial assay office.

Exeter 1710 - John Elston

No item of this period was hallmarked in Ireland (the Union Act date later: note 6), in Birmingham and Sheffield (their assay offices were not yet in operation). No item hallmarked as "Britannia standard" seems to have been assayed in Edinburgh, notwithstanding this was possible after 1707.
Since 1720, although the "Britannia standard" could be used as optional standard throughout the UK, only in London it was used in such an extensive way to allow the survival of a significant number of examples. Only on items made during the Victorian era or in more recent years some rare example of "Britannia standard" silver with other assay offices hallmark can be found.

London 1896 - George Fox

Birmingham 1911 - Levi & Salaman

London 1901 - Erbert Charles Lambert (probably over struck to the maker mark)

Edinburgh 1906 Thomas Smith & Sons (note that the "Britannia" is added to the full set of hallmarks)

ENDNOTES:
1:    Britannia silver should be distinguished from Britannia metal, a pewter-like alloy containing no silver.
2:    In the last part of the 17th century, the "clipping" and melting down of coinage became a serious problem to the Crown. In 1696 William III began "The Great Recoinage" with an Act to "encourage the bringing of wrought plate to be coined". This Act introduced milled coins (which cannot be "clipped"), and raised the standard of wrought plate to 95.84% pure silver
3:    The new standard was compulsory throughout the United Kingdom but only in 1700 the Assay Offices of Chester, York, Exeter and Norwich were brought into line (Newcastle only in 1701). Scotland was not at that time under the jurisdiction of Westminster and the higher standard was not in use. Furthermore also after 1720, when the unification of silver standards in England and Scotland was made, the  Britannia standard  was very seldom used in Scotland.
4:    The strategy to prevent melting of coin for producing silverware was changed with the introduction of a duty of 6 penny per troy ounce of wrought silver.
5:    Notwithstanding this order, occasionally are found marks which do not comply with it.
6:    The  Britannia standard  was never in force in Ireland. Some confusion can arise with silver marked in Ireland where a mark similar to the Britannia (the Hibernia) was in use as duty mark between 1730 and 1807. After the Union Act of Ireland with England and Scotland and the adoption of the English system of hallmarking, the Hibernia became the symbol of the Dublin Assay Office.

Hibernia	Britannia

To distinguish the two marks, consider that the Hibernia rests her arm on a harp, while Britannia rests her arm on an oval shield