Mobile phone operators have until December 11 to put down a deposit and apply for a spot in the UK’s upcoming 4G spectrum auction, says Ofcom this morning. The telecoms regulator has published a timetable for the auctions, which it claims will be the largest ever sale of mobile airwaves in the UK. A reserve price of £1.3bn has been set on the total spectrum being auctioned. Operators will need to apply to take part in the bidding process and put down an initial deposit by December 11 and will be informed if their attempt was successful in February or March next year. New 4G services will go on sale as early as May. Ed Richards, Ofcom’s chief executive, said: “Today marks an important shift from preparation to the delivery of the auction, which will see widespread 4G mobile services from a range of providers. The entire industry is now…