Normally, the caller’s number will show on your phone screen and this may be enough for you to determine whether this is a customer or a friend.

If you would like to know what number the caller has dialled before you answer, you will need Dialled Number Identifier (DNI). This is available at a cost of £9.95 set up and £2.50 per month. It can be set up within the number management area of your online account.