Odd to say, but BT and its' many, many resellers, have had a major outage from Friday night (app 1730GMT) and if your particular ISP ( or reseller) has been affected, then wait until tomorrow before slinging sh*te - but there again if it is playing up, how do you post, or receive?
Mine was up sh*t creek until last night, but my neighbours' net was open and that is how I got to bore the pants off you all on Saturday.
Totsiens!
Conan.