Channel 4 is to withdraw itself from 4 Digital Group, the consortium which was awarded a licence for the second national commercial DAB radio multiplex last year.
The future of former 5 Live editor Bob Shennan, who joined the group to oversee the launch of a number of new digital channels, is unclear.
Channel 4 informed Ofcom this morning, to which they replied: "Ofcom recognises that the economic environment is very challenging and that all organisations need to make decisions in light of the circumstances they face.
"Ofcom and the Government have supported DAB through the licensing of services and Ofcom continues to believe that DAB offers listeners real benefits. There are now 7.7 million DAB devices in the UK with 11 per cent of all radio listening through these."
It is not yet clear where this leaves the remaining investors in the 4 Digital Group – Bauer Digital Radio Limited, Carphone Warehouse Group plc, Sky News Radio Limited, Global Radio Ltd, UTV Radio (GB) Limited and UBC Media Group plc.