not as far as i'm aware, but each time you open one you have a credit check against your name - the more you open, the less likely you are to get accepted.
I'm not sure it makes much difference provided you only have small overdraft limits. But you may find that even if you close the account it stays on your record as the bank may still keep it partly live just in case any pending payments go through.
What's your motive- are you opening as many as possible of these accounts that offer maybe £50 if you open one?
factor30 - 5% is blerdy good interest in the current climate and many current accounts restrict this great interest rate (far higher than ISA or savings) to £1k or £2k so the more you can have, the better.