Anyone ringing an Orange or One 2 One phone is in for a particular shock. From 19 February, the cost of calls to these mobiles from an ordinary phone will almost double, to 30p per minute during the day and 20p per minute on weekday evenings.
The new prices were announced the week before Christmas, when many presents were already under the tree.
The mobile phone networks claim they were making a loss on calls from fixed phones and point out that their phones still cost less to call than rivals Cellnet or Vodafone (37.5p a minute on weekdays). However, users may feel entitled to be upset, given that cheaper incoming calls might well have been a reason for choosing a particular phone.
Mobile phones are just one of a growing band of special-tariff numbers that can inflate normal phone bills. And such is the plethora of new services on the market that it is not always easy to spot which are the expensive numbers: BT's published list is five pages long.
National Phoneday two years ago made some headway in helping to highlight potentially expensive numbers by giving an extra 1 to all standard phone numbers. But even so, there are exceptions. Some pagers have ordinary sounding numbers, but extraordinary costs: 015231 numbers cost 54.99p per call; 014263 cost 24.68p.
Phoneday did little to distinguish free, low-cost and premium lines. BT's free and reduced- rate numbers are reasonably well known (0800 and 0345, respectively), but more telephone firms are entering the market, each with their own numbers for free or low-cost calls.
Personal numbers - which track down subscribers wherever they are - also underline the confusing range of prices. Mercury's recently launched Call Direct (0541), costs the national long-distance rate to call. Competitors operating personal numbers starting with 07 cost far more. Some cost 16.7p per minute peak rate, some 30p and some 41.05p; and the numbers themselves are hard to tell apart.
Elsewhere, large companies such as the insurer Equitable Life are switching their publicly published numbers to the 0990 or 0541 codes. This brings advantages to companies by simplifying their administration but not to callers. Call an 0990 number and you will pay the long-distance rate, even if the company has its offices in the next street.
The long-distance charges differ from phone company to phone company, and are higher from payphones, mobiles or using chargecards.
There are other traps for the unwary. Advertisers have to state if a number is premium rate,
but it is usually in small print. The 0990 code - 8.79p per minute peak, the UK national rate - is very similar to premium rate 0991. One wrong digit could prove expensive: 0991 calls are 149.99p a minute at any time.
There are further pitfalls calling and using mobile phones. Vodafone and Cellnet answer automatically if a phone is out of reach, and callers pay to get this response. Free-call numbers are not free from all mobiles. And if your mobile fails, some networks' customer service numbers are on mobile codes that are free from the handset but at the full rate from an ordinary phone.
This week, Oftel, the telecoms regulator, is expected to announce proposals that will improve the situation. According to its consultation documents, ordinary numbers (geographic in the jargon) will start 01 or 02, mobiles, pagers and personal numbers will start 07, free, local and national rate calls 08, and premium rate codes 09. But some will not change until 2001, though Oftel will be encouraging premium rate numbers to move to 09 as soon as possible.
The phone companies accept that the current situation leaves much to be desired. "We sympathise with customers," a BT spokesman admits. "It can be confusing, and it is something the industry should look at."
At the same time, the companies are asking for the new system to be introduced slowly so they can move customers over to it gently. The prognosis of many is that confusion will worsen before it improves, as old and new numbers run side by side.
IT'S DEAR TO TALK
Mobile phones Cost to call per minute
0958, 0973, 0976 30p peak, 20p off-peak, 10p weekend
0831, 0370, 0378 37.5p peak, 25p off-peak, 12.5p weekend
Orange and One 2 One are slighly cheaper to call than Cellnet or Vodafone
014264 8.23p peak, 3.95p off-peak, 3.29p weekend
014266 24.675p at all times
015231 54.99p peak, 34.9p off-peak
0898 49p peak, 39p off-peak and weekends
0891 50p peak, 45p off-peak and weekends
0991 149p at all times
07000 16.71p peak, 9.85p off-peak and weekends
07050, 07060 41.05p peak, 28.32p off-peak
National-rate calls (long-distance charge regardless of call distance)
0990, 05415 8.79p peak, 7.29p off-peak, 3.29p weekends
0345, 0845 3.95p peak, 1.65p off-peak, 1p weekends
0800, 0500, 0321 Company with the number pays all the cost
All prices include VAT. Call BT on Freephone 0800 800 891 for a free copy of "The Call Price Leaflet for Residential Customers".