when did the new £1 coins come into circulation
One pound (British coin) Since 28 March 2017, two versions of the one pound coin have been in circulation – the original round design and a new dodecagonal (12-sided) design.[3] As of March 2014 there were an estimated 1,553 million round £1 coins in circulation,[4] of which the Royal Mint estimated in 2014 that 3.04% (i.e. about 47 million) were counterfeit.[5][6] In an effort to counter this, the Royal Mint introduced the new 12-sided coin, which is bimetallic like the current £2 coin, and features an undisclosed hidden security feature called 'iSIS' (Integrated Secure Identification Systems).[7][8] The round pound will remain in circulation until 15 October 2017. After that date, the older coin can only be redeemed at banks.[9]