The first (Confirmed) Counterfeit 12-sided 1 coin

Although only one of the trial types (Yes, there were two types) it marks a dangerous stepping stone.

Personal opinion is these may have been a private commission (from China) with the original intent to deceive the collectors market, but two bags (40+ coins) were listed on eBay as "error or copy".

(Click for coin statistics)

Unfortunately I don't have an original Trial Piece to compare, so have compiled this image (with kind permission) using images Check Your Change

Due to the enormity of the changeover from "round" pound coin to the new 12-sided bi-metallic one, the Royal Mint made hundreds of thousands (Exact Number soon) to be sent out to "industry stakeholders" for the updating of mechanical devices etc to allow the acceptance of the new coin. The contracts signed by those companies required ALL of these coins to be returned to the mint at the end of December 2017. This meant they shouldn't be in the hands of the general public, and this obviously meant coin collectors wanted them! They were selling like hot cakes for well over 100 at one point. The price has since started dropping but is now pretty stable at around 50-75. The legality of owning one though, is still somewhat of a grey area and stories of the Royal Mint confiscating coins and contacting buyers requiring them to return the coins they bought from third parties were rife (Most facebook groups banned their sale). With such a high potential return per coin, it peaked the interest of the counterfeiters.
The counterfeit coin itself is not great (It lacks even an attempt at the obverse micro-printing and the portrait is lacking detail) but given its similarity to the real thing, had they been copied from the circulating coins design, they would have no trouble circulating.

Copyright The Fake Pound Coin Database.