I have no TV and recently received a visit from an inspector. I say I received it - I was at work at the time so I just got a note through the door telling me that they'd call again. The wording is interesting at the part where they tell me why I might require a licence:
"You need a TV Licence to use any television receiving equipment such as a TV set, set-top boxes, video or DVD recorders, computers or mobile phones to watch TV programmes as they are being shown on TV."
I remember from my old flat that they used to specifically mention TV-Tuners in relation to computers in their threatening letters (I also remember I let the nice man in to poke about my flat and they still kept sending me letters, so they won't be coming in this time!)
As I understand the law 'as they are being shown on TV' means 'at roughly the same time as they are being shown on TV', rather than the easy to mis-read 'as they are being shown on TV at some time or another' - consider a lawfully purchased DVD of some or other BBC show.
I also seem to remember the BBC News site having some text near the video streams stating ~it is our opinion that you need a TV licence to watch this in the UK~.
It seems that they want to trick people into buying a licence even when there's no lawful requirement these days.
The question I find interesting is - what if I am using a webcam to chat to a mate and I can see his telly in the background? Do I then fall foul of the law and need to ask him to move the camera or turn off the telly, or does it become a narrowcast and not a broadcast? (Also do I care? If I was that bothered I'd buy a TV Licence and watch TV - as it is I can spend the best part of the evening catching up the day's news from El Reg which is a whole lot more entertaining than the shite I remember seeing on telly).