I believe that you can have a debit card from 16 (or maybe earlier). It will be a Solo or Electron card. These accounts are more restricted, especially regards overdraft facilities and other sorts of credit. They may also have higher charges or penalties because the young user is considered a risk, also they may not be as widely accepted. These cards are also available to people with bad credit ratings, whereas a Visa Debit or Maestro (the old Switch) card will not be.

Credit cards on the other hand are only available to over 18s.

Why are you asking us anyway? Go to you local banks and find out what they offer.