The launch of the BBC's test high-definition TV service looks likely to be put back until the end of the year. And no, it's not because Blue Peter is corrupt. The delay in BBC HD TV is down to the brains at the Beeb being unable to decide which protocol to use.

But it's not entirely their fault (the HD TV thing, not the cat-naming travesty). Ofcom needs to decide what's going to happen to freeview before Auntie Beeb commits to a high-definition protocol.

The BBC will definitely offer a high-definition service, but it will remain limited to satellite viewers until industry regulator Ofcom decides what it is going to do with the freeview digital terrestrial service. To obtain the bandwidth required to put up the HD broadcasts, five BBC DTT (Digital Terrestrial TV) channels will have to be spiked.

The plan as it stands is for test HD broadcasts to run during the early hours, between 0200 to 0600. Expect a lot of programming aimed at new mothers and MMORPG freaks.

To view the tests you'll need an Mpeg4 set-top box but, depending on Ofcom's decision, you may need to reinvest in more expensive equipment. If Ofcom decides to completely revamp freeview, you may require a DVB-T2 decoder, for instance.

The BBC Trust released a statement that said: "It would be possible for the BBC to launch this service almost immediately. However, the possibility of a major reorganisation of the DTT platform introduces the prospect that future HD services may be provided using the DVB-T2 transmission protocol on a dedicated HD multiplex.

"This would require consumers to have DVB-T2-capable set-top boxes and so calls into question the proposal to provide a four-hour overnight service on freeview from next year using the existing DVB-T protocol.

"On this timescale, users would have to upgrade their set-top boxes in the short-term in order to gain Mpeg4 capability to receive the four-hour interim service. Then they would face a second upgrade to gain DVB-T2 capability in order to receive the full nine-hour service (as well as HD propositions from the other PSBs)."

The BBC Trust will make a final decision at the end of November.