Twenty Pence

The twenty pence coin was introduced in 1982 to provide a convenient denomination between the ten pence and fifty pence coins, easing everyday cash transactions as prices rose after decimalisation. Like the fifty pence, it uses a seven-sided (Reuleaux heptagon) shape rather than a plain circle.

While not as widely collected as the fifty pence for commemorative themes, the twenty pence coin is notable to collectors for a well-documented mule error variety from 2008 in which coins were accidentally struck without a date.

By the early 1980s, rising prices meant that everyday transactions increasingly required a denomination between the existing ten pence and fifty pence coins, prompting the Royal Mint to introduce the twenty pence piece in June 1982. It was given the same distinctive heptagonal shape as the fifty pence to keep the family of British coin shapes visually consistent while remaining easy to tell apart by size.

The coin's design was updated in 2008 as part of a wider redesign of UK coinage in which the reverses of the standard circulating denominations were reworked to each depict a segment of the Royal Shield, forming a complete image when several coins are placed together.

That 2008 redesign produced the coin's best-known collecting curiosity: because of a transitional overlap between old and new obverse/reverse dies, a small number of 2008-dated twenty pence coins were struck using an old obverse paired with a new reverse that both lacked a date, resulting in genuine "undated" 20p coins entering circulation.

The coin is seven-sided (a Reuleaux heptagon), struck in cupro-nickel, giving it a silvery appearance, and is smaller than the fifty pence but shares the same basic shape family.

The obverse carries the reigning monarch's portrait, while the reverse has featured a crowned Tudor rose (pre-2008) or a segment of the Royal Shield of Arms (2008 onward, as part of the coordinated Royal Shield redesign across denominations).

The famous 2008 "undated" error can be identified because neither the obverse nor the reverse carries a date at all, an easily verified and well-documented mint error rather than a normal date variety.

Ordinary circulated twenty pence coins are worth only face value. The genuine 2008 undated mule error is the standout exception, and confirmed authentic examples have traded for hundreds of dollars, reflecting genuine scarcity and strong demand among British error-coin collectors, though prices vary with certification and condition.

Because the undated error has been widely publicized, buyers should be cautious of coins that have simply had the date worn away through circulation, which look similar but are not the genuine mint error.