Government departments have been told to stop using premium-rate phone lines for core public services.
Guidance issued by the Cabinet Office admits it is "inappropriate" for members of the public to be hit with high charges. (See our Say No To 0870 guide for tips on avoiding them.)
The move comes after a damning National Audit Office report found that callers, including crime victims and the bereaved, spent £56 million on expensive Government numbers last year.
Calls from landlines to 0845 numbers typically cost between 1p and 11p a minute. From mobiles, they usually cost between 14p and 41p per minute.
The new guidelines state: "It's inappropriate for callers to pay substantial charges for accessing core public services, particularly for vulnerable and low income groups.
"01, 02 and 03 numbers are all charged at standard geographic rates and are always included in available minutes within call packages.
"Departments should therefore first consider whether a non-geographic number is required, and if not, use a 01 or 02 prefix.
"Where a non-geographic number is needed, departments should treat the use of the 03 prefix as a default policy position for the provision of key public services."
When 0845 numbers continue to be used, an 03 alternative should also be offered, according to the document.
Departments will have to explain themselves to Cabinet Office ministers if they do not abide by the rules and provide numbers with 01, 02 or 03 prefixes.
Richard Lloyd, executive director of consumer group Which?, says: "This guidance is a step in the right direction, but it's disappointing no deadline has been set and public bodies will still be able to use expensive 0845 numbers.
"People should not be left out of pocket when calling essential services so we need to see these new rules brought in as soon as possible, so that every government department plays fair."
Earlier this month, a ban on customer service lines for airlines, train operators and major retailers using 084 and 087 numbers was announced. (See the Premium rate number ban MSE News story).