Some taxi drivers are said to be using a hidden miniature mirror to try to look up the skirts of back-seat female passengers. The rectangular mirror, estimated at 6cm by 11cm, is typically affixed to the top right-hand corner of a cab's dashboard window with a suction cup. It is angled from the top down, allowing a driver easy and undetected observation of a back-seat passenger from the chest down. A police spokesman said it was very difficult to prove the intent of such a mirror: 'Each driver will give you different excuses, like to observe rear traffic congestion or to check what his passengers are holding.' However, he warned: 'Ladies wearing miniskirts must be very careful of these settings.' One driver said it was common knowledge that such mirrors were used to look up the skirts of female passengers in the rear seat. 'It's no big deal really,' he said. 'Not many drivers have them, but there are some who don't see a problem with using the mirror to stare at their female passengers' legs.' Passengers can overcome the problem by sitting directly behind the driver, or even asking the driver to take the mirror down.