The INQ1 device from manufacturer INQ, owned by 3's parent company Hutchison Whampoa, integrates Facebook along with Skype, Windows Live Messenger and music site Last.fm.
Facebook will be on the phone with one-click access and live updates will be pushed to the front screen of the device. INQ also allows users to directly upload pictures to their Facebook profiles from its 3.2 megapixel camera.
INQ will be available free on a contract tariff from £15 per month offering unlimited free Facebook, Skype, Windows Live Messenger and web access, plus 75 minutes of calls to other networks, unlimited texts, unlimited email and unlimited free 3-to-3 calls. INQ will also be available on PAYG at £79.99 with internet packages available from £5 per month.
Mark Zuckerberg, CEO of Facebook, said: 'More than 15 million Facebook users currently access the site through their mobile devices. This number has doubled over the past six months, and we expect it to continue to grow as people become even more familiar with handsets like the INQ.'