A fake email that claims to be from Marks and Spencer, and offers recipients up to £500 in vouchers, has resurfaced again, over a year after its first appearance.

Security firm Sophos reported that the email chain letter, which was first seen in the summer of 2007, has generated ten times the usual number of queries on its website in the past two weeks.

The email says M&S is testing "word-of-mouth advertising" in conjunction with Persimmon Homes. To receive the vouchers recipients are asked to forward the email to their contacts. "Within 2 weeks you will receive an email with your vouchers attached," it reads.

Hoax emails are a real nuisance," said Graham Cluley, senior technology consultant at Sophos. "Shoppers are more eager than ever to seek out the best bargains online, but unfortunately this one is too good to be true - I'm afraid all anyone who replies to this email will receive is disappointment. Email users should always search the web to see if an enticing offer is real or phoney before sending it on to their friends."