0800 numbers are Non Geographic Numbers (NGN). This means they have a National presence and are not restricted to a specific location. They work alongside your existing landline or mobile telephone number. 0800 numbers are called Freephone numbers and are very attractive for customers as they are free to call from UK landlines and UK mobiles. 0800 Freephone numbers are perfect for generating new business through advertising and marketing campaigns as they can increase customer responses.