O2 started 2007 with a solid lead in customer numbers, with Vodafone and T-Mobile trailing behind O2's 17.6 million.
T-Mobile's total customers fell from 17.2 million to 16.9 million in 2006.
The battle for new customers in the fourth quarter was tough, with Vodafone winning by miles. O2 and T-Mobile both found between 200,000 and 300,000 new customers, while Virgin Mobile struggled.
Virgin's net customer additions for the final quarter of 2006 slumped to just 11,100, compared with over 192,000 in the final quarter of the previous year.
The network blamed its lower-than-expected customer growth on increased price competition and higher advertising spend from mobile customers.
Over six million of O2 and Vodafone's customers are now on contract, and both businesses are doing a high percentage of their business direct.
T-Mobile's contract customer base represents 22% of total customers, compared with 17% a year ago. The network's total contract customer base increased 25% to 3.7 million. However, the operator's prepay customer number remains higher than other operators' at 13.2 million.LinksT-Mobile contract focus at expense of prepayO2 signs 136,000 new contractsVirgin struggles for connections