The bi-metallic £2 coin is the largest circulating coin denomination of the Pound Sterling. It was introduced in 1998 (earlier two pound coins were made of Nickel brass, were intended as commemorative, and did not circulate much). Being bi-metallic means that the coin comprises two separate components of differing alloys; it also features a special security device at its centre.
The Royal Mint maintains a "definitive" style of the £2 issued annually, as well as a large variety of one-year circulating commemorative types and some Non-Circulating Legal Tender (NCLT) £2 coins for collectors. Between 1997 and 2015, the definitive type was this "Technology" type representing the advances made in industrial and technological fields; its reverse design spirals outward from the Iron Age core, to the Industrial era, the age of the computer and finally ends with the outer ring symbolising the Internet. Designed by Bruce Rushin, the reverse’s central area contains a latent feature which, when tilted, transforms the image of four separate scrolls into an image of eight intertwined scrolls. The edge inscription STANDING ON THE SHOULDERS OF GIANTS was taken from a letter written by Sir Isaac Newton, acknowledging how much he owed to the work of others.
When the first bi-metallic £2 coin was struck, it established a number of important milestones in British numismatic history. It was the first base metal £2 coin intended for general circulation (the other coin denominated as two pounds is the gold Double Sovereign which is a bullion coin), the first bi-colour coin of the United Kingdom made of two different alloys, and the first British coin to incorporate a latent feature as a security device.
The first bimetallic £2 coin was launched on 15 June 1998; the coins had been struck earlier and were dated 1997. The outer ring is Nickel-Brass (76% copper, 4% nickel, 20% zinc); the inner circle is CuproNickel (75% copper, 25% nickel).
In 2015, the new Britannia type two pounds coin was launched and became the definitive type of the denomination. The Technology Two Pounds continue to circulate and are still legal tender. | 
