UK Visa advice - Conference in Scotland July 2012

I have 2 Chinese students in my lab in Italy who are awaiting their UK visa for a conference next week in Edinburgh. They submitted their application 2 weeks ago in Rome but so far still no reply and now it looks like they'll lose their conference, flight and hotel bookings.
Is it because of the Olympics that there is this delay for UK visa processing? Has anybody else experienced any problems like this in the past? Does anyone have any advice on how to speed up the process?