British mobile network operator O2 UK has announced the expansion of its 4G LTE services to Northern Ireland with Belfast and Lisburn as the first cities to be switched on. They will be followed by Londonderry by the end of the year, Telegeography.com reports on July 2, 2014. Now reaching 21 million people, O2 says that its 4G network is being rolled out to one million people every month until it reaches 98 percent of the population.