Thousands of the new £1 coins – described as the most secure in the world – have reportedly been produced with major flaws.
Some of the coins have been found to appear cracked and misshapen, while others even have the middle missing, The Sun reported.
The coins, which have a gold coloured ring and are silver in the middle, went into circulation in the UK in March.
However, officials are said to have admitted that faults have crept into the minting process.
John Taylor, a coin collector from Crystal Palace in south London, has a £1 coin with no middle.
New 12-sided one pound coin - In pictures
He told The Sun: “It is a definite Royal Mint error. The sellers claimed they had come from a sealed bag from the bank, which in turn came from the Royal Mint.”
Some of the mangled coins are already said to be selling as collectors’ items on eBay for thousands of pounds.
It is not clear how many of the coins are faulty.
A spokesman for the Royal Mint, which is based in south Wales, told the Standard: “The Royal Mint produces around five billion coins each year, and will be striking 1.5bn new £1 coins in total.
"As you would expect, we have tight quality controls in place, however variances will always occur in a small number of coins, particularly in the striking process, due to the high volumes and speed of production."
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