(Telecompaper) UK regulator Ofcom has confirmed that it is delaying the start of an auction for 4G spectrum previously used by the Ministry of Defence (MoD), reports BBC News. In a statement, the regulator said that it had received letters from Hutchison and Telefonica, parent companies of 3 UK and O2 UK, threatening legal action over its plans to start the auction before the EC completes an in-depth investigation of their mobile merger. Ofcom had been due to accept applications from December, followed by an auction in February/March 2016. With the EC decision expected in May, any auction is now unlikely to happen before summer 2016.