No longer just a place to send letters and exchange money, the Post Office is set to add another service to its ever-expanding list of utilities: mobile contracts. The company announced today that it's joining the list of providers that rely on EE's network to launch its own mobile service in the UK. It'll initially be sold online, over the phone and in 50 Post Office branches this autumn, with a view to expanding nationwide later this year (if it's successful). The move will see it take on supermarkets like Tesco, Sainsbury's and Asda, which all offer mobile packages in addition to home phone and broadband bundles, but also bigger players like Virgin Media. There's currently no word on cost, but given the large number of players in this market (currently standing at 24), the Post Office will likely need to price tariffs competitively to get customers to grab a mobile SIM along with their car tax renewal.