status.zensupport.co.uk has info about outage in North of England but my sites in Aberdeen, Glasgow and Belfast look as if they are out at the moment - since 08:13
As I understand it traffic from Scotland and NI would be backhauled to Zen's POPs in the North so were probably affected by the outage.
Virgin (ADSL) => Namesco => Newnet => O2 => Plusnet => Zen => Newnet => Zen Lite 8000
Note: I don't lay turf for anyone. astro or otherwise, all views and opinions expressed are my own based on experience.