Whose are these numbers at 20p a minute??
These are numbers in the mobile services (071 to 075 and 077 to 079) range of numbers which have high termination rates and which therefore cannot be inclusive in call allowances. For the period April 2014 to April 2015, Ofcom has capped mobile termination rates at 0.84p per minute but currently this applies only to the major networks. Other providers are required to charge 'fair and reasonable rates' for call termination.
These numbers are used for a variety of purposes. Some are used by international dial-through providers. Others are used by various other interactive and automated systems. These termination rates can be up to 15p per minute. Some ranges are used by very small mobile networks who keep the cost of calling out from their network down by subsidising their costs from the high termination fees gained on incoming calls.
Another set of non-inclusive mobile numbers exists: those in Jersey, Guernsey and Isle of Man. They also have slightly higher than usual termination rates and are outside of Ofcom's control. Numbers starting 070 and 076 are not mobile numbers. They also have high termination rates such that callers, not users, fund the provision of the service. Ofcom will review 055, 056, 070 and 076 usage and pricing in the next year or so.