BBC Newsnight is broadcast over the UK terrestrial airways every weekday at 10:30pm on BBC Two. They also broadcast their latest nightly programme over the Internet for 24 Hours after each programme. Here is the link to the low quality .wmv stream
Newsnights general mission is to make sense of the days news from a UK perspective, explaining details behind current events etc.
There are also watch again features, visit Newsnight website for more details.