The Royal Mint of the United Kingdom, which makes the country's circulating coinage, is also very active in the bullion coinage space and issues many bullion coins which are legal tender.
Additionally, it also makes bullion which is not legal tender and is targeted at investors and not at coin collectors - such as this one.
The Royal Mint says about this product:
"This gold bar contains 20g of 999.9 fine gold and depicts a poignant image of Britannia clutching her trident. The Roman deity, from which the British nation earns its name, is a timeless embodiment of the country’s pride, strength and progress. Jody Clark’s design is a fitting symbol of what the bar offers investors looking to add bullion to their portfolio – strength and resilience. The flat-edged, 20g gold bar is imprinted with a unique serial number and presented in secure, Britannia-branded blister packaging for safe transportation and storage.
A clear, removable film is included on the packaging to protect the blister while in transit. It can be removed once the product has been received, without affecting the original value."
The type of packaging described above is referred to as "in assay" by bullion dealers. The bar is "minted" (struck using minting techniques similar to a coin, and not cast in the way that larger investment products are).