Counterfeiting coins doesn't sound as exciting as pumping out ersatz $100 notes, but it is definitely a thing, especially in the UK where one in every 30 pound coins isn't the real McCoy. To battle this, over the next year the government will phase out the old coin for a shiny new one that incorporates "a high security feature ... to protect it from counterfeiting in the future".
Part of me kind of wishes that "feature" is latinum, but somehow I doubt that's the case. For obvious reasons, the official information site for the new coin doesn't go into detail, other than to say:
The High Security Feature added by The Royal Mint means that for the first time, 100% accurate automatic recognition is possible on a genuine or counterfeit coin.
In addition, it'll be made of two metals -- a nickel-brass outer ring and an inner nickel-plated centre and feature a hologram that switches between the pound symbol and the number one. The coin will also be "better" than it's currently circulating counterpart -- 0.35mm thinner and 0.75g lighter -- however, it'll be bigger: 23.43mm compared to the 22.5mm.
The new pound will make its debut in March of next year, where it'll be legal tender alongside the old coin until late 2017. From that point onwards, the old coin will be accepted as deposit-only by banks and post offices.