In the UK, phone numbers are classified as Geographic, UK-wide, Mobile, Business Service, Premium, Emergency & Non-Emergency, Directory Enquiry, Freephone Service, Not-for-profit Service, Public Service, etc.
As per the standard ‘UK Calling’ System, as defined by Ofcom, UK’s independent communications regulator, the cost of calling any phone number is determined by the digits it starts with, your phone network provider and whether you use a landline or mobile.
The cost of calling a particular number class, especially service numbers from a mobile or landline is split into an access charge payable to phone networks and a service charge decided by the organization owning the number. The access charge for a specific type of call will be clearly mentioned by the service provider on the bills and when you take a contract with them.
Numbers starting with 0800 or 0808 are called Freephone numbers. As per the standard system, all Freephone numbers starting with 0800 and 0808 are universally free to call from all phones, whether it’s a mobile or landline number.
It may not be possible for customers to call up some Freephone numbers (0800 or 0808) via payphones. Due to the additional charges involved, some organizations are not keen to support incoming calls from payphones. A customer will have to pay for calls to Freephone numbers from International or Overseas Roaming numbers.