Just to be slightly more precise on this point: you have to be watching a "television programme service" at the same time as it is being broadcast - but the licence is necessary even if you're watching it on cable or a phone or iplayer or whatever, as long as it's live.Crankarm said:However you actually have to be watching live broadcast TV as well.
Streaming Iplayer of yesterday's TV (or watching your neighbour's video recordings of last night's programmes) is perfectly OK without a licence.