The British government has introduced a new one pound coin that has a hidden security feature to make it difficult to counterfeit The new coin, which comes into circulation on Tuesday, is thought to involve material inside the coin itself which can be detected when electronically scanned by coin-counting or payment machines, according to the (BBC).
But officials at the Royal Mint have not released any further details. Other security measures include an image that works like a hologram, and micro-sized lettering inside both rims. 
As a result, the Mint claims it will be the "most secure coin in the world". It will replace the existing 1 pound coin, of which about one in 40 are thought to be fake.  "It's been designed to be fit for the future, using security features that aim to safeguard our currency, and currencies around the world, for years to come," said Adam Lawrence, chief executive of the Royal Mint. 
The old coin will remain legal tender until 15 October this year, after which shops are under no obligation to accept it.    
After that date, consumers will have to take the coin to a bank to exchange it.
Supplies of the new coin have been delivered to 33 banks and post offices throughout the UK, including seven in Scotland, three in Wales and two in Northern Ireland. They will gradually become more widespread over the next few weeks.

Source: QNA