10. Magnetic Ink Character Recognition

Each day, banks process millions of cheques. It would take them far too long to manually enter the data from each cheque. They use a technique called 'Magnetic Ink Character Recognition' (MICR) which enables them to process 300 cheques per minute with 100% accuracy.

At the bottom of each cheque are a series of numbers which record:

• the cheque number
• the bank or building society sort code
• the customer's account number

These numbers are written in a special ink which contains iron particles. This ink is magnetised and commonly called 'magnetic ink'. It can be read by a special machine called a Magnetic Ink Character reader (MICR).

The MICR will only recognise numbers printed in a standard font using the magnetic ink. This provides a high level of security because any attempt to alter the magnetic ink printout with normal ink by writing over it will be ignored.

Both the Reader and the magnetic ink are expensive and so are generally only used by banks.