By the summer, the tax people at HMRC say they will have stopped ripping people off through the use of costly 0845 numbers.
People ringing for tax help using a mobile can pay 41p a minute after dialling 0845. Typically they then have to wait 6 minutes and millions are kept waiting for more than 10 minutes.
From April, calls about Child Benefit - which is now being taken away from high earners -- will be via numbers with the 03 prefix, which is already being used for tax credit enquiries.
03 calls should count as part of inclusive minutes in a phone contract and are charged at the same rate as 01 or 02 numbers.
All customer calls will be switched to the 03 prefix by the "end of the summer" according to HMRC officials who were giving evidence to MPs today.
Here's a useful guide to phone number prefixes.