It was expected that Channel 5 would take the fifth channel on Freeview HD, but the Richard Desmond-owned broadcaster withdrew its application for the slot last December.
Media regulator Ofcom then handed the spare digital terrestrial television (DTT) capacity on Multiplex B back to the BBC, leading to speculation over what the corporation intended to do with it.
The last time this situation occurred in 2010, also after Channel 5 had opted against bringing Channel 5 HD on Freeview, the BBC used the capacity to launch BBC One HD, a simulcast of its flagship channel.
Under the BBC's Delivering Quality First efficiency drive, the corporation announced that the existing BBC HD channel would change to BBC Two HD, a HD simulcast of the channel.
This plan still stands, meaning that HD content from BBC Three and BBC Four will no longer have a home. However, the BBC has ruled out using the available Freeview HD slot to maintain BBC HD or launch another HD network.
As the corporation says it has 'no need' for the spare HD capacity on Freeview, it has instead asked for potential bids from the wider TV industry.
BBC bosses have engaged with other broadcasters, content providers, channel operators, TV platforms and media owners on potential plans for the channel slot. An advert for the spare capacity was also run in Broadcast magazine.
Interested parties have until midnight today to register their interest in the channel slot, after which the sale process is expected to last "a number of months depending on the number of parties involved".
"Any party interested in launching a television service or services (e.g. broadcaster, content provider, channel operator, TV platform, media owner) can express an interest in bidding for the capacity," said the BBC in a statement.
"Subject to the BBC's approval, it will be up to the winning bidder as to how the capacity is utilised. In line with the BBC's Fair Trading guidelines, the BBC will apply fair, reasonable and non-discriminatory processes in the handling of all aspects of this sale process and the selection of the winning proposal."
ITV operates HD simulcasts of ITV2, ITV3 and ITV4, but they are thought to be locked in to an exclusive deal with Sky as they have still not yet launched on Virgin Media.
UKTV, the joint venture between BBC Worldwide and Scripps Networks Interactive, operates various high definition channels including Eden HD, Good Food HD, Watch HD and Dave HD - and it could look to launch one of these on Freeview.
Another possible bidder may be Channel 4, which operates HD versions of E4 and Film 4 on Sky and Virgin Media.
The broadcaster that secures the HD slot will get a big potential audience, as Freeview announced in February that 1.3 million Freeview HD integrated TVs and set top boxes were sold in the final quarter of 2011, and the platform now has 2m active users.
What type of new HD network would you like to see launch on Freeview? Let us know in the comments below: