Orange Mobile UK provides a service called "Call Barring," with which you can block both incoming and outgoing calls, regardless of whether you are inside the UK or abroad. Using this service, you can put an end to any annoying calls that you receive on your phone. Through outgoing call barring, you can prevent any number from being dialled on your phone. Orange doesn't charge a fee for this service.
Press the main "Menu" key on your phone or the "Action" key, depending on the handset model you have.
Go to "Settings."
Scroll to "Phone" option, and press the selection button.
Scroll down to "Call Barring."
Select a call blocking option, such as "All Outgoing" or "All Incoming." Then select "Activate" and enter the password. The present password for call barring on Orange network is "1111."
With call barring on, you can still dial emergency "999" and "112" numbers.