The new 12-sided £1 coin entered circulation, but its hidden security feature has Nottingham residents baffled and bemused.

The coin was introduced today and despite originally being only slated for purchase in specific parts of the country, you could get them from the Royal Bank of Scotland in Old Market Square, and the Post Office on Queen Street.

However, there’s a secret security feature hidden on the coin that most people were unaware of.

The new pound coin website said the coin has a number of features which make it much more difficult to counterfeit, including latent image, micro-lettering, milled edges and the hidden high-security feature.

We asked the people of Nottingham if they knew what the feature was.

Julie Sullivan, 44, a retail specialist at the Post Office on Queen Street, said: “Initially selling the new coins was quite slow, not a lot of people knew we were selling them, but it picked up very quickly.”

When asked about the hidden security feature she said: “I’m not 100% sure what it is, but a little boy asked me what’s new about the coin and I told him that there was a little dragon inside protecting it.”

Not everyone was as enthusiastic, or imaginative, about the hidden feature.

Jack Betts, 18, front of house staff at McDonald’s, said: “Whatever it is, they’ll find a way around it. Eventually, they’ll crack it. It is just a matter of time before it gets cracked.”

The old pound coin will cease to be legal tender on October 15 2017.