The UK 0845 number code is a special telephone number, in which the calling party is charged a special rate for the call by the telephone operator, regardless of the actual cost to route the call. Instead the called party pays or receives any differential in the charges for the call to the telephone operator, usually based on factors such as the amount of usage the number experiences, the cost of the trunk lines to the facility, and possibly a monthly flat rate service charge. The numbers are used by commercial entities and public sector organisations.