Ofcom consumer research suggests that 32% of households have HD TV channels. As Ofcom says, this may be an overestimate, since not all consumers distinguish between having an HD TV and getting HD channels. However, we know that at least 28% of households receive HD channels, given the Sky HD households mentioned above, plus the 3.8m cable customers (though a few of the latter may not have HD sets). Freeview HD households are on top of this. For the purposes of discussion, let's say a round 30% of households can watch HD.
Several UK channels broadcast in both SD (standard definition) and HD. In HD households, it is a simple manner of selecting the HD version of the channel to get the higher video quality. The interesting thing is, audiences generally don't bother.
ITV1 is the largest UK commercial channel (and second only to BBC1 overall), and broadcasts in both modes. The average person watched 5 hours, 46 minutes of ITV1 (SD+HD) per week in December 2010. Of this, 14 minutes was of ITV1 HD. Of course all this HD viewing came in HD households, so that implies the average ITV1 HD viewing was 46 minutes in those households.
However, this means that in households with the option to watch ITV1 in HD, viewers chose to do so for just 46 minutes out of their 5 hours 46 minutes of ITV1 viewing in both modes, or 13% of their viewing.
This is a striking result. Even in these HD households situation, where consuming exactly the same programme in HD rather than SD is simply a matter of clicking a few buttons on the remote, 87% of the time audiences simply don't bother.
This doesn't prove HD is irrelevant, but it does suggest it has limited general value for audiences. It is, for instance, likely more valuable for films or sports than for quiz shows.
Which brings us to superfast broadband. HD is regularly cited as one of the strong arguments for superfast, and often features heavily in proposed 'app stacking' (multiple activities in a single home using one broadband connection). However, if consumers see HD as irrelevant to most of their viewing, then it's hard to justify spending large sums on superfast to bring it to them.
Moreover, the strength of the internet for TV is in on-demand programming (since broadcast works perfectly well for linear TV). But sports are very heavily consumed live. Most countries already have infrastructure to deliver HD TV versions of sports channels and programmes, be it via terrestrial, satellite or cable. Superfast therefore adds very little to HD live sports.
This leaves movies as the key remaining TV content that might have substantial value as on-demand HD, and therefore contribute to the case for superfast (though cable VOD is also capable of this). This is a limited use, and certainly not used heavily enough to contribute regularly to an 'app stack'.
Thus those building the case for superfast on the back of HD need to explain why they expect consumers both to become much more interested in high definition and on-demand services than they have been to date.
[Note that for the purposes of this simple analysis I have ignored issues of secondary sets and different channel shares in HD/non-HD households, though these are unlikely to change the outcome materially]