Like many other mints, the Royal Mint issues bullion coins in precious metals, having much higher intrinsic value than their face value. The half ounce (1/2 oz) gold coins are denominated as Fifty Pounds (£50).
The coins are legal tender but are not intended for circulation. They are targeted at bullion investors or collectors who appreciate the special editions as pieces of art. The mint makes a distinction between plain "bullion" coins (issued in Brilliant Uncirculated grade) and proofs; the "bullion-grade" coins have textured backgrounds of both the obverse and the reverse designs and use the generic "authoritative" design, while proofs are typically "one-year" types. They are usually issued in parallel with other denominations/sizes having the same reverse designs.
Britannia as a symbol has been depicted on British coinage for centuries. The bullion series called Britannia has been issued in gold since 1987 and in silver since 1997; it has a "definitive" depiction - used on bullion coins (Brilliant Uncirculated grade), as well as “Britannia, the Changing Face of Britain” - a series of one-year designs like this one - used on proofs made for collectors.
The 2016 design shows a proud, patriotic Britannia with the British lion at her feet, a familiar pairing in popular history. With Britannia representing the nation, the lion is often used to depict the courage and strength of the British people. The lion is at rest, ready to rise at her command to the defence of the realm.
Sculptor Suzie Zamit is the first woman to have designed a coin featuring Britannia, the iconic female symbol of Britain. The 2016 Britannia is her third design for The Royal Mint, following her design for the 2010 Britannia coin range and the 2009 Charles Darwin Bicentenary £2 coin. Susie has brought her own perspective to Britannia, "the warrior queen".
“I knew it was important to make Britannia immediately recognisable but I also tried to think about how she could represent Britain in the twenty-first century. Britannia represents British liberty and democracy, especially potent in times of national insecurity, so I wanted to portray her as a strong figure, almost Amazonian, proud, patriotic and courageous. She is reminiscent of the goddess Athena, a warrior but in a protective, peace-keeping way.
The shield, a symbol of protection and security, incorporates the Union Jack and I included the lion as national symbol of courage. Visually it is very strong, beautiful and watchful and also a symbol of protection. The inclusion of wind and sea reflect the more modern, forward thinking themes of renewable and green energy.”
This half ounce gold proof coin was issued in sets only, not individually. | 
Search for United Kingdom: Gold Half Ounce 2016 Britannia, Proof on eBay 