Over the next few months, every bank cheque will incorporate water-fugitive inks that smudge when wet.
They will also be solvent-sensitive, to show whether attempts have been made to change the name or sum on the cheque.
The banks' move is part of a continuing battle against fraud by the Association for Payment Clearing Services (Apacs), which introduced tough new guidelines in January.
All the main banks declined to give details on the levels of fraud they suffer. But a Barclays spokesman claimed figures for the entire industry showed an increase over the past three years.
Jonathan Banks, an executive in the Apacs standards unit, said: 'The technology of colour photocopiers, scanners and printers is becoming increasingly sophisticated.
'You can get photocopiers which turn out very good imitations of a cheque, except that the ink from photocopiers does not run.
'The measures are aimed at trying to counteract things before they get too bad.'
A normally invisible bank symbol will also have to be present on a cheque. It will be visible only when it is placed under an ultraviolet light.
Banks are also changing the design of their cheques to make forgery more difficult. The alterations include cutting down the length of the 'pay to' line - to prevent fraudsters from adding another person's name to the cheque.
Barclays and Lloyds are devising more elaborate cheques to make them more difficult to counterfeit.
Doug Hopton, deputy head of fraud prevention at Barclays, said: 'Before the new cheque books were introduced, we had seen a significant increase in attempted cheque fraud.'
Although most attempts were foiled by vigilant staff, the bank still needed to increase its own technical sophistication to defeat the fraudsters, he added.Reuse content