Over the last 18 months, counterfeiters have started using recycled paper to print forged notes. But the motive is not as environmentally conscious as it appears because the green paper passes at least one anti-forgery test.
More and more shops and pubs are installing devices on their counters which shine ultraviolet light on to notes. Manufacturers claim the boxes help people to distinguish between forged currency, which fluoresces, and genuine currency, which does not.
But forgers have found that recycled paper, which is less white that ordinary, bleached paper, hardly fluoresces at all - so can easily be mistaken for real money if checked in this way.
The pounds 40 boxes have also been found lacking if a note has been inadvertently passed through a wash - perhaps by being left in a trouser pocket.
Detergents that include a bleaching agent will leave the note 'whiter than white' - bright enough for it to fluoresce under a ultraviolet box and be marked out as a forgery. This could cause shop owners and the police considerable embarrassment.
A new pounds 99 version of these detector boxes, combining both a ultraviolet light and an ordinary white light, helps to get round the problem. The new box, on show at the International Police and Exhibition and Conference at the Barbican this week, was developed by the European Design Consortium, a Bedford-based company. It consists of a flat surface, lit from beneath by an ordinary white light. An ultraviolet light shines down on the note from above. The flat surface contains a filter that absorbs frequencies from the white light that would normally destroy the effect of the ultraviolet light.
If a note fails to fluoresce - which means it could be genuine or a fake printed on recycled paper - the box lets people check easily for other tell-tale clues to its origins.
One is a shadowy 'ladder' effect caused by an oily deposit left by rollers as they run across the note to create the characteristic broken metallic strip. Only if the note fails to fluoresce, and the ladder shadow and the right watermarks are in place should the note be taken as real.
Paul Bishopp, director of EDC Marketing, said 'recycled' forgeries are becoming more common.
'The first lot - pounds 350,000 worth - showed up in Blackpool 18 months ago. Real money is now being rejected because it has been washed in people's jeans, and forgeries are getting accepted,' he said.
The Metropolitan Police said the new box might prove useful, particularly to help pick up forged MOT certificates.Reuse content