I note that the link to Barclays Bank explains the difference between Direct Debits and Standing Orders, which 'millerxxx' requested.
There is however another payment which ought to be avoided at all costs, and that's the Continuous Payment Authority.
This payment is not set up by yourself, but is like a Direct Debit in that it's set up by the organisation you're paying into. Unlike a Direct Debit though, there's no guarantee, and no way you can do anything about controlling the amount or the frequency money is taken from your account.
If something does goes wrong, you're the one who will have to liaise with the rogue company and attempt to get things back on course.
Unlike a Direct Debit, you cannot instruct the bank or building society to stop or amend the payments.
http://moneyfacts.co.uk/guides/banking/what-is-a-continuous-payment-authority/