Channel 4 has purchased a new slot on the non-subscription digital terrestrial service Freeview.
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The space will initially be home to a time-delayed version of C4's drama and factual spin-off More4 - but could be used for a new channel in future.
The slot was sold for a reported £12m after being put up for auction by National Grid Wireless.
Five and Disney were believed to be among the other bidders for the latest Freeview channel.
"Capacity on Freeview is a scarce commodity and this deal allows us to accommodate our full current line-up of free channels on the platform and to keep our options open for further channel launches in the future," said C4 chief executive Andy Duncan.
C4's current Freeview offerings comprise Channel 4, E4, E4 +1, More4 and Quiz Call.
Five has recently bought a stake in Top Up TV, the pay-TV operator that offers extra channels to Freeview viewers.
The network said it hoped the deal would present opportunities to launch new free-to-air digital services during 2006.