Every now and again, a software company finds a customer who is so passionate about the power of one of its products that he – or she – becomes one of its one most vocal marketing agents.

Colin Clark, corporate cost audit manager for supermarket chain Somerfield, is no stooge, but his company has so benefited from using Veritas' Enterprise Vault email management software that he has happily been recruited as one of the product's most vociferous evangelists. At the Veritas global user conference in May, Somerfield won a ‘Vision' award for the way it has transformed an area of its business using a Veritas product, saving more than £3 million to date.

For users of Microsoft's Exchange server product – and market share figures suggest that means most businesses – Somerfield's story starts in a familiar fashion. A couple of years ago users were struggling to manage a huge weight of emails, and were often becoming overwhelmed, losing track of valuable information. Some users had .PST files (stored Microsoft Outlook email files) of more than 2 gigabytes. Overall, with 3,500 Exchange users, Somerfield was sending and receiving 100,000 external emails a month, in addition to internal emails. The problem was particularly worrying because Somerfield managers use emails to negotiate with buyers – and many of these were being lost, with considerable financial consequences.

Clark realised that solving the problem with a reliable and easily searchable email archive would be enormously beneficial to several areas of the business; the finance department could save money by accurately tracking and rationalising negotiations with suppliers; legal requirements on data protection, document retention and so on would be more easily met; HR would be better able to investigate alleged employee misbehaviour; and the IT department would be relieved of some of the burden of managing Exchange, one of its most troublesome user-facing applications.

The answer came from a small UK software company, KVS, which was later bought by US storage software giant Veritas, and whose product has since been renamed Enterprise Vault. It works by capturing, compressing, de-duplicating, indexing and managing emails sent and received by Microsoft Exchange.

The software was installed in March 2002 and has revolutionised Somerfield's email management. It now stores 11 million emails, every one of which is recoverable within a few seconds. Its retention policy? "We keep them all," say Clark.

"The greatest benefit is the ability to search and discover the truth. Nine times out of ten, critical business information resides with the corporate email system."

The success of the project can be measured in real financial terms: Somerfield employs an auditing firm to attempt to recover any money owing to it that it may have lost track of. Before this was a painstaking process, involving paper and trawling through Exchange mailboxes. Now, using Enterprise Vault, Clark estimates that he has saved £3 million in two and a half years.

There have also been cases where Enterprise Vault's rapid searching capability has solved business problems unexpectedly. On one occasion he was able to kill off an allegation that details of Somerfield's Christmas promotion had been emailed to a competitor.

In a third example, the Office of Fair Trading asked all supermarkets for copies of correspondence with other supermarkets within 28 days. While some rivals asked for an extension, it took Clark 15 minutes to get the data.

Somerfield's policy now is that users can keep old emails, but only up to 30 megabytes. If someone needs to retrieve old email, they must provide a good business reason, and Clark will undertake the search, which takes a few seconds. He gets about 20 to 50 requests of this type a month, which "equates to no more than an hour's work".

Clearly, the most controversial aspect of Somerfield's email management is its decision to keep all emails – a policy that might potentially infringe data protection laws. For this reason, it is under review. But Clark insists he is not worried that stored emails may provide a resource for any litigious adversaries: "The chances of benefit in this area [i.e. regulatory issues] exceeding the benefits of improved administration are very small."