be careful if you get some from barclays or alliance and leicester banks. They are aware of the spam being sent in their names, so do not reply to them unless you are 100% sure they are real. if in any doubt print out the email and take it into your local branch. i insisted on a written statement saying which were real and which werent, so I can claim any losses.
Usually, you can tell from the address, if it is something like surveyxxm101csr_user_account@barclays.co.uk, it is suspicious. just be careful and spam shouldnt get a chance to cause you trouble