O2 (UK) congestion. BT Cellnet launched the world's first GPRS network on 22 June 2000, although GPRS-enabled devices were uncommon at that time. O2 publicly announced on 15 December 2009 that it had successfully demonstrated a 4G connection using LTE technology installed in six masts in Slough. The technology, which was supplied by Huawei, achieved a peak downlink rate of 150 Mbps. In January 2012, the company announced plans to provide free internet to millions of residents and visitors in central London, by launching Europe's largest free Wi-Fi zone, along with free Wi-Fi access for anyone on any network in and around
O2 (UK) certified with the Carbon Trust Standard in recognition of its commitment to reduce its carbon footprint. O2 attained the standard after saving 47,000 tonnes of carbon over the previous three years through its energy efficiency measures, including a £1.4 million distribution of smart metering technology across the company's cell sites, offices and retail stores, and upgrades to more energy efficient systems across its mobile phone network. In addition to distributing energy efficient LED lighting and boiler system controls, the company was also able to reduce energy use by removing air conditioning units from some of its cell sites and reducing