I work for three mobile "Three UK is a British telecommunications and internet service provider operating as a subsidiary of CK Hutchison Holdings, operating under the global Three brand. The company launched in March 2003 as the United Kingdom's first commercial video mobile network. It provides 3G and 4G services through its own network infrastructure."-wikipedia
The Three mobile services were launched in the UK on 3 March 2003 (03-03-03, for publicity purposes), with handsets going on sale (such as the NEC e606 and Sony Ericsson Z1010) later that month. This made Three the UK’s first commercial video mobile network. On 9 December 2004, Three announced that it was the first network to meet its regulatory requirement of 80% population coverage in the UK.
A Three UK store in Royal Tunbridge Wells, England
Three's first retail stores (3Store) opened at the same time as the network launched, on Oxford Street and Kensington High Street, both in London and at the Birmingham Mailbox. Three's handsets and contracts are also sold by mobile telephony chains and independents throughout the UK, as well as online retailers. In 2005, an expansion of the 3Store portfolio saw stores opened in larger shopping centres throughout the UK, such as the Bluewater and The Mall at Cribbs Causeway near Bristol. On 24 October 2006, Three announced that it had purchased 95 high street shops from O2 and The Link.
Three launched SeeMeTV, allowing its customers to submit their own video content that other subscribers could watch. Users would make a small micropayment (the price decided by the video's creator) to watch these videos. The user who created the videos would get paid 10% of the amount of money paid by other users to watch the video. Users were paid once they had accrued £10.
In 2010, Three became the fourth network to launch the iPhone after O2, Orange and Vodafone, and was voted Best Network for Mobile Broadband in a YouGov survey for the second year in a row.
In July 2014, Three introduced three InTouch apps  enabling Three customers within the UK to route calls and text messages via a local Wi-fi network where the Three mobile signal is intermittent or unavailable. The initial registration of the app requires a connection to the Three mobile network for authentication after which customers can utilise any connected Wi-fi network. Three customers can access the Virgin Wi-Fi network implemented at over 130 London Underground stations, three InTouch app permits voice, data and text messaging to continue without loss of service. Currently, the inTouch app does not perform a handover between Wi-Fi and mobile networks thus a call in progress via Wi-Fi will be dropped if the user moves out of signal range regardless of whether a usable mobile network is available.
On 24 March 2015, Three's parent company Hutchison Whampoa announced it would acquire the UK operations of O2 for £10.25 billion, subject to regulatory approval. On 11 May 2016, EU commission blocked the purchase of O2 on the grounds that it would affect competition in the UK market.
In order to provide coverage parity with other networks in the UK, Three initially maintained a national roaming agreement with an established 2G network operator. Until 2006, O2 operated this service for Three customers. However, Orange was selected as the new national roaming partner from 10 May 2006.
Since Three invested heavily in 3G technology since its inception and wanted to run a 3G only service (which in turn would make infrastructure costs cheaper, which could be passed onto the consumer) it was criticised in the early days[by whom?] for offering a very patchy 2G service in favour of 3G, when 3G had not fully caught on enough to achieve mass adoption, and Orange 2G was adopted in areas as a fallback where 3G wasn't available. The 2G fallback coverage provided by Orange has since been removed as Three believes 3G and 4G technology is now sufficient for mass adoption - and as a result, older phones that support only 2G networks are not compatible with the Three networks. From 2013, Three no longer provided a significant 2G fallback for most of the United Kingdom.
On 18 December 2007, T-Mobile and Three launched a 50:50 joint venture called Mobile Broadband Network Limited (MBNL) which aimed to combine both of their 3G networks and provide almost complete 3G population coverage by the end of 2008. On 12 November 2010, MBNL announced that the network had reached a total of 12,000 combined sites.
Three's 4G Ready logo
Three began a limited rollout of 4G LTE services in December 2013 in London, Birmingham, Manchester and Reading expanding to over a further 450 locations by the end of 2014. In August 2012 Three was given permission to use part of the 1,800 MHz spectrum used by EE's 4G network. On 20 February 2013 Ofcom announced that Three had been awarded 2 x 5 MHz of 800 MHz to use for its 4G rollout. Three planned to launch 4G in the second quarter of 2013, however, it delayed the rollout until Q4, saying that it wanted to analyse the performance of other networks' 4G coverage first. The network provides LTE and DC-HSDPA service as a standard feature to all its subscribers using "Ultrafast" to describe both technologies, making it the cheapest price for 4G and the only unlimited 4G in the UK. On 23 April 2015, Three announced that VoLTE would be rolled out along with 800 MHz spectrum from September.
Until 2009, Three subscribers in the UK, Ireland, Austria, Italy, Denmark, Sweden, Hong Kong and Australia could use their service on Three networks around the world for no extra charge with "3 Like Home". The service was relaunched on 30 August 2013 as "Feel At Home" for UK customers visiting Australia, Austria, Denmark, Hong Kong, Ireland, Italy and Sweden where calls, texts and data consume the same amount of purchased airtime "minutes" as for communication within the UK. Since then, additional countries have been added to "Feel At Home" including Finland, France, Indonesia, Israel, Macau, New Zealand, Norway, Spain, Sri Lanka, Switzerland and the USA. The service was expanded to a further 24 European countries in September 2016. This does not include calling from the UK to these or other countries. Fees can reach 46p per minute for calling most European countries from the UK.