Some criminal types send out thousands and thousands of emails at random saying the email is from NetWest, or Abbey, or Barclays or whatever.
Of course many of them will go to people who dont have an account at those banks so they delete it. But enough do to make it worthwhile.
These emails will direct you to a fake web site that has been set up to look like a real banks web site.
So you click on the link, and it takes you to this fake bank web site, where you type in your userid and password.
These criminals "capture" your userid and password, logon to the REAL bank web site with your details, and steal all your money.
So NEVER believe any email that says it is from an organization asking you to logon to a web site to verify your details. This could be a bank, but also Amazon, ebay, Tesco, BT, MSN etc etc etc.
Also NEVER click on a link in an email as it may take you to a fake site rather than a real one. Always type the web address into your browser, or click on your favorites to go to the site.
NEVER click unsubscribe on a scam email as it only verifies your email address is live so you will start to get more spam.
Always treat ANY email you get as suspicious. Sad to have to do this, but now you have got one spam email you may start to get more.