Lancashire Grid for Learning - Please read
I have put up a post on the LGfL forum here: Board Message
Which basically asks you to prune any old\redundant accounts from the mail server, and to ask staff to clean up their mail boxes as I'm pretty sure that they don't need 6 years worth of email ;)
Anyway, the reasons are given on the LGfL Forums post and if you are not yet a member please note that you need an .lancsngfl.ac.uk or .lancs.sch.uk address to register and be an LGfL school, not from a unitary authority, to join. I shall authorise accounts as soon as I can.