It has become a real economies of scale battle for mobile device users now. Orange and Vodafone yesterday both reported growing mobile subscriber numbers, but the revenue derived per user declined for both companies in the fourth quarter.

In separate statements, the companies said that previous declines in the average revenue per user (Arpu) have begun to stabilise. Vodafone in particular pointed to 'seasonal effects' for the decline in its fourth quarter Arpu figure from the previous quarter.

Orange's overall per-user average revenue was £246 in 2001, compared to £280 in 2000. That decrease was due mainly to the number of prepaid customers in the first half of the year, Orange said. People with annual contracts spend a lot more — Orange made £550 per contract user in 2001, compared with £525 in 2000.

Vodafone's average dropped to £274 in the UK in 2001, a decline of £7 in the October to December period, the company said.

For the quarter ending 31 December 2001, Vodafone reported 99.86 million registered users, half of which were prepaid customers, the company said. That figure has now exceeded the 100 million subscriber mark.

For its part, Orange reported a customer base of over 39 million customers by the end of 2001, 12.39 million of whom live in the UK.

O2, the renamed wireless division spun off from BT in November 01, will release its fourth quarter subscriber numbers on 5 February.