I'm on UKOnline, and I can assure you that my internets were quite fleeting and unusable at the time. It made for quite a boring day. 

Problems didn't seem to last more than 12 hours though.

I had such issues too, and I'm in another country and on another ISP.
Not that not everybody has some issues from time to time with his ISP but these were a bit odd, like certain sites disappearing and some being slow while the rest ran at normal speeds, exactly as described here.

They've finally resolved the problem for me, although apart from the hell of not being able to visit the inquirer, and may partner surfing to Digg on her lunch break via terminal services, I conveniently couldn't connect to a good portion of the sites I was developing for.

Ha Ha

I was wondering why my SPAM had dropped so sharply

more like global crossing this morning... cause some major issues

always check on here
http://internetpulse.net/
http://isc.sans.org/