Mobile giants Vodafone and O2 have both now flicked the switch and made their 4G networks live in the UK.

O2 will initially go live in London, Bradford and Leeds, reaching around five million people.  Vodafone’s network will start out within the capital.

The aim for both companies is to have the network live in 13 cities by the end of 2013.  Both companies will be focusing on the same locations: London, Leeds, Leicester, Bradford, Birmingham, Coventry, Edinburgh, Glasgow, Liverpool, Manchester, Nottingham, Newcastle and Sheffield.

The eventual aim is for the network to cover 98% of the UK.

EE got a head start on both companies by launching its 4G network back in October last year, and is already serving 105 towns and cities within the UK.  By the end of June, EE had already signed up 687,000 4G customers.

At the Ofcom auctions in February, both firms spent big; Vodafone invested £802m and O2 £550m.

Both companies are trying to lure customers in with bonus content, such as content based around music or sports; however, 4G remains more expensive that traditional 3G networks.

Vodafone’s UK chief Guy Laurence said that he now expected 4G to take off, with users wanting access to data-hungry applications and content on the move.

Speaking to Sky News, Mr Laurence said: “I think adoption will be far faster than 3G, which was ten years ago, because people didn’t really understand how to use it”.

The other main mobile network, Three, has said that it will launch its own 4G service in December, initially in London, Manchester and Birmingham.  Three has said that it does not plan to charge extra for the service.