The new phones, the latest offering in an increasingly fierce marketing war with Vodafone, have been developed with Motorola. They allow calls to be made on either of the two main types of digital network in common use, GSM1800 and GSM900, and are claimed to be the basis of the first truly international phone network.
The dual-mode Motorola mr601 phones will cost 15 to 25 per cent more than conventional models, and start at about pounds 125. Orange claimed it would have a lead of three to four months on its competitors in introducing the dual-mode technology, which searches out the correct frequency automatically.
They are aimed at enticingbig-spending business travellers away from Vodafone and Cellnet. Orange customers will receive one bill itemising calls made in any of the 50 countries.
Orange customers can now call in 10 countries and the plan is to extend this "roaming" capability to at least 24 by the end of April, almost 40 by the end of August and more than 50 by the year-end. For the first time, British mobile phone owners will be able to use their equipment in North America.
Hans Snook, managing director of Orange, said: "This is another step in our ambition to allow our customers to use Orange through one phone on one number at home, in the office, or abroad."
Orange now has more than 785,000 subscribers and its UK coverage has grown to 92 per cent of the population.
Forecasts for growth of the British mobile phone market were raised last month after record figures for subscribers numbers were released by the two all-digital networks, Orange and One2One, helping Orange shares recover after a lacklustre few months.
Orange added 125,000 customers to its networks between October and December, including an encouraging Christmas, its highest quarterly connections figures.
The network also grabbed 29 per cent of all new customers in the market last year, compared with 15 per cent in 1995. Orange claims to be in second place behind Vodafone, with more than 1 million digital customers, but ahead of Cellnet and One2One.