Exchanges that matter...

I think that what Alex really should say 'No'. What he saying is
that for Xara UK-sourced traffic is split like this:
  50% is sent to UK peers at the LINX in London
  40% goes to the USA
  10% goes to dGIX in Stockholm

Doh! Yes. Must get reading lessons. Missed the word "remaining".

Currently I have no foolproof way to differentiate traffic that
goes over the LINX destined for in UK and outside UK. There's
some work going on to build a list of UK ASes to this end (amongst
others) but it hasn't been done yet.

Jim is quite right (except it works bidirectionally).

Alex Bligh
Xara Networks