Everything Everywhere has rebranded itself as EE, on the day 4G mobile services are finally launched in the UK.
The firm will use network infrastructure from its subsidiaries Orange and T-Mobile to deliver super-fast mobile broadband services in the 1,800MHz frequency band.
EE has also announced plans for a fixed-line fibre broadband service, and the launch of a 4G Wi-Fi dongle to assist people accessing the internet on the move.
Orange and T-Mobile will continue to run their own networks, with the former targeting premium users and the latter concentrating on the budget end of the market.
"London will be the first major European city to be covered by 4G," said EE Chief Executive Olaf Swantee.
"We plan to have 4G services available to 20 million in the UK. The EE network will cover 70 per cent by 2013 [and] 90 per cent of [the] UK by 2014."
Pilot services will launch in four UK cities today (Tuesday September 11th) - London, Birmingham, Cardiff and Bristol.
EE is planning a full consumer launch across 16 cities in time for Christmas - ensuring mobile device users will be able to take advantage of faster download and upload speeds.
4G is due to go live in Edinburgh, Belfast, Leeds, Sheffield, Manchester, Liverpool, Glasgow, Newcastle, Southampton, Hull, Nottingham and Derby before the end of 2012.
Commenting on the launch, Matthew Howett, Practice Leader in Ovum's regulatory telecoms team, said the launch of 4G would help bring the UK out of the "slow lane".
He noted that countries such as Angola, Azerbaijan and Uzbekistan have already launched 4G mobile services, meaning Britain is playing catch-up.
"However, that is all set to change as Everything Everywhere’s new brand for 4G mobile services - EE – has announced plans for its rollout," Mr Howett stated.
"The decision to cover London in its entirety from day one makes it one of the most ambitious rollouts we have seen, and EE is clearly not wasting any time making up lost ground."