ITV and Channel 4 are expected to announce they are joining the BBC, Sky and Crown Castle UK in DTV Services, the company that markets Freeview.
In March Freeview chairman Peter Abery, also chief executive of Crown Castle UK, said he would welcome ITV and Channel 4 as additional shareholders in the consortium promoting take-up of Britain's fast-growing digital terrestrial platform.
Since then the commercial broadcasters have increased their involvement in Freeview, with ITV acquiring multiplex A in April, the same month that Channel 4 launched entertainment channel E4 and its catch-up sister channel E4+1 on the Freeview platform.
Since E4 and E4+1 had previously been subscription channels the move marked a major shift in Channel 4's multichannel television strategy, and an acknowledgement of Freeview's growing importance.
ITV and Channel 4 have since confirmed new channel launches, with Channel 4 launching its More4 adult entertainment channel tonight at 8pm, and ITV due to launch men's channel ITV4 on November 1, and a children's channel in February.
Stakes in DTV Services will allow ITV and Channel 4 to have a bigger role in shaping the future of Freeview, which media buyer Zenith Optimedia said was due to overtake Sky in 2008 to become the UK's largest digital television platform.
Freeview's growth—it currently has nearly 5.5m UK homes to Sky's 7.4m and digital cable's 2.6m—could be boosted further if ITV and Channel 4 directly marketed the platform.