Gerry Coppell, a controller in Nationwide's technology department, said the company will roll out the system across its network of 681 UK branches by early 2003 for customers opening 'Flex' current accounts.
The eventual aim is to use the system for about 70 processes that require a signature, although it will not be used for cash withdrawals for a couple of years, he said.
Biometric security techniques, such as fingerprint recognition or iris scanning, offer banks and other businesses greater protection against computer crime and fraud.
But some critics have claimed the public will not accept such technologies. Nationwide's implementation will be watched closely by other financial institutions. The system, developed over the past two years, is based on technology from UK firms Florentis and Motion Touch, and sits on a Microsoft .net platform.
An electronic pad on the counter records a profile of a customer's signature, which is then embedded in an electronic document and used to verify future transactions.
The system takes account of variables such as pressure, speed and acceleration of writing, which it records 200 times a second, and the physical characteristics of the signature and the time taken to complete it. It is more secure than the current method of keeping signature cards at the branch, Coppell said.
The embedded signatures do not present a security risk, out of context, he said.
"The only way this could be [used to prepetrate a fraud] is with the connivance of the person whose signature it is," he said.
In the late 1990s Nationwide conducted the first pilot tests of iris recognition at cash machines and counters, but ditched it when it proved too expensive.