Over at skyuser we received the following message from the server hosts earlier this evening :-
Within the last 30 minutes, the London Internet Exchange (LINX) has a major problem that caused instability and loss of connectivity. Our bandwidth providers have shut down their connections to LINX so we are no longer directly affected by it.
However, as LINX carries such an enormous volume of traffic (and the majority of the UK's internet traffic) it is quite possible that some connectivity may still be less than perfect as other providers may still have their port enabled and/or have congestion on other circuits.
this was some time ago