Mobile phone subscribers will be able to keep their telephone number and prefix when they switch network operators from next week, in a move designed to boost competition in the market.

From next Friday mobile users will be able to keep their prefix (087, 086, 085) and the last seven digits of their number when they defect to a rival network. The changeover process will be free of charge for users, although they will have to pay any outstanding charges to their former network.

Subscribers will be able to switch operators in just a few hours rather than days, when the new €30 million computer systems goes live. It should enable consumers to move much more easily if they see a particular mobile package that they like, says Ms Etain Doyle, chairwoman of the Commission for Communications Regulation.

"It will remove the issue for consumers and business people of having to change their contacts and stationery," she says. "Research we did in 2001 showed mobile number portability would benefit business and consumers by about €100 million."

Telecoms analysts believe the new number portability system should help the firms with the least number of subscribers. Mr Darragh Stokes of Hardiman Telecommunications says it should be a boost for Meteor - which has just 4 per cent of the market.

"It means long-term, O2 and Vodafone business subscribers can consider Meteor's rates without worrying about the cost of changing their literature or business cards," he says.

Not surprisingly, Mr Andrew Kelly, Meteor's director of corporate affairs, agrees and the firm is planning a new marketing campaign over the next few weeks to drive home this message.

"From our point of view it offers us a big opportunity," he says. It coincides with Meteor's move into the business market and will enable us to target consumers with the message that we can deliver savings of 35 per cent over the other networks.".

"For a lot of mobile users, including consumers, having a mobile number was like having a bank account: once you had one you didn't move. Now there is a real opportunity to attract new subscribers," says Mr Kelly.

By giving consumers more choice, mobile number portability should reduce the ability of the big two operators to produce such high-profit margins, he adds.

But Mr Niall Norton, chief financial officer at O2, says it also represents an opportunity for the bigger firms to add customers.

An O2 survey completed to coincide with the introduction of mobile number portability found that 55 per cent of consumers would switch operators to get better value for money, he says.

"I think the small business customer is the most obvious beneficiary of the new system. Previously they would find it costly to switch networks because of the price of printing new stationary and having to update their contacts. We are bullish about the opportunities provided by number portability," says Mr Norton.

The scale of the engineering job required to introduce the new number portability system was an even bigger job than adapting O2's computer systems for the introduction of the euro.

"We almost had to build a completely new database which recognised subscribers by different codes rather than their previous numbers," said Mr Norton. "It was like open heart surgery."

The mobile operator's computer system should be capable of switching about 1,000 mobile numbers per day. And all the firms are confident that the system will not crash next week, despite similar complaints in Australia when it introduced a similar system in September 2001.

Ms Tara Delaney, Vodafone's director of communications, says the company has invested two years of planning in the mobile portability project, which involved the changing of more than 160 processes in the firm.

She said Vodafone's strong brand recognition would enable it to take advantage of mobile number portability.