The coins' magnetic properties are weak and last only as long as the coin is in contact with the magnet. Nevertheless, the property can be exploited in numerous intriguing games.
Robin Willson, Professor of Biochemistry at Brunel University, has devised several such games since he discovered the coins' special characteristics over Christmas. He has applied for patents on three of his latest ideas - all potential executive toys. One is a 'magic box' that enables you to 'pick winners' by hiding a magnet inside a box filled with coins.
Professor Willson discovered the phenomenon when he found a magnetic keybox with a mysterious object stuck to its underside in his garden. This turned out to be a coin.
'I knew it couldn't be a British coin, because these are not magnetic,' Professor Willson said. 'But on closer examination, it turned out to be a 1p piece . . . I thought it must be a forgery.'
Apart from patenting his ideas, he has also contacted the Science Museum, which is keen to incorporate the coins' intriguing properties in one of its public exhibitions. He tried out his new games on the children at St Bartholomew's hospital in London and they were immediately fascinated. The explanation for the coins' magnetism is straightforward. In its September 1992 issue of coins, the Royal Mint changed the composition of the metal it used to make its 1p and 2p coins. Prior to 1992, these coins were made of bronze (97 per cent copper, 2.5 per cent zinc and 0.5 per cent tin). From September 1992 the composition changed to mild steel coated with copper. Steel, with its iron base, is very weakly magnetic.
The change was an attempt to cut the costs of producing the coins. The cost of producing conventional bronze pieces had already exceeded their face value, the Royal Mint said.
Other European coins, including all Dutch coinage, are capable of being magnetised.