The pre-decimal twopence (2d), also known as a "half groat", was a coin worth one one-hundred-and-twentieth of a pound sterling, or two pence. It was a very short lived denomination. A large copper piece was issued in 1797 only (before the United Kingdom of Great Britain and Ireland was established on 1 January 1801, so technically belonging to Great Britain and not the UK). In 1817, silver twopence coins were issued for circulation, then again in 1818 and 1820, after which it was decided the coin was too tiny to be practical. During Queen Victoria's reign, they were issued again in three separate years, mainly for use in the colonies.
Coins of the same size and virtually the same design (but with proof-like finish) have been issued regularly since 1817 and continue to be released every year as part of Maundy sets; these are listed separately under "Maundy Twopence" in the NCLT section.