From this year all new 5p and 10p coins will be made from steel rather than the traditional cupro-nickel. The move will save the Treasury up to £8 million a year as steel is a lot cheaper than the mix of copper and nickel used previously.
Steel weighs slightly less for the same volume than cupro-nickel. So to keep the new steel coins the same weight and diameter as the old ones they have to be slightly thicker – 1.9mm rather than 1.7mm for a 5p. That extra 0.2mm does not sound much but it will be enough to make many coin slot mechanisms reject the coin.
Lower value coins, 1p and 2p, changed from bronze to steel in 1992 and the price of copper has risen so much those older coins are now worth more for scrap than the face value (though it is illegal to melt them down or export them).
It will be many years before the metal in older 5p and 10p coins are worth more than 5p or 10p for their metal. But steel is much cheaper to buy and lasts longer. A nickel plating will ensure the coins look the same.
The move to steel was announced in the Government’s spending review in autumn 2010. The change was delayed until the start of this year, partly to give the vending machine industry longer to make the necessary changes. The Treasury admits that the costs to the machine operators will probably be £80 million but could be as high as £124 million.
The new coins are being minted now but the Royal Mint says it will be April before they start appearing in our change and the autumn before they become common. Only then will any problems become apparent. So when you pull a handful of change from your pocket to put in a coin slot machine a quick sort with a magnet will pull out the new steels and leave the old cupro-nickel coins that will definitely work.