The proposal will cause disruption and extra expense for long-standing users, who will have to change stationery and inform contacts. Oftel claims that the move is justified because industry figures show that "on average" users only keep a mobile phone for two-and-a-half years.
The four main networks have been quick to point out that the figure is misleading because many people have actually kept the same mobile phone for up to 12 years, and that the low average is caused by corporate clients who sign up for a few months to take advantage of cheap deals but then move on to other networks when those expire.
Phone operators also say that the move will delay the introduction of "number portability" - by which somebody could retain the same phone number even though they change between networks.
Portability would reduce the cost of changing between networks, because it cuts down on reprinting of stationery, for example.
The proposal has been largely overlooked since its publication earlier this year, because it came at the same time as suggestions for new numbering systems for cities across the country.
It would mean that all mobile phone numbers would start with the prefix 07, which would also be used for pagers. Vodafone will begin allocating the first such numbers later this summer, after receiving an allocation from Oftel earlier this month.
Presently, mobile phone numbers can begin with a number of prefixes, including 09, 08, 04 and 03.
In 1995, following the "Phoneday" in which all fixed numbers were changed to start with 01, Oftel declared that 04- numbers would in future denote mobile phones. But then it reversed its decision.
The regulator said yesterday that the reason for introducing the 07 prefix was that people wanted to know when they were calling a mobile phone, as the existing variety meant that it was not always obvious from the number.
But one network operator pointed out yesterday that this solution will not be perfect because besides mobile phones the 07 prefix will include "personal" numbers, which are guaranteed to reach any number, fixed or mobile, and pagers. All could have different pricing regimes.
"We're not as convinced as Oftel that grouping all the numbers under the 07 prefix will help people know what the charge for phoning will be," said one industry source. Charges for calling mobile phones can vary enormously, depending on the location and network of the phone.
The technical cost of changing mobile phone numbers will almost all be borne by the networks. "The market in the UK is too competitive for us to do anything else," said a spokesman for Vodafone.
Mobile phone operators expect that the Oftel measure will be brought in alongside other changes such as renumbering for British cities.Reuse content