The first BarcampUKGovweb had 50 session slots for around a hundred participants. Typically the sessions were 25 mins. BarcampUKGovweb09, although going on an hour longer, had only 30 slots for some 120 plus (?) participants. To me this ratio is getting just too far away from the spirit of barcamp: "8th Rule: ..., you HAVE to present. (Ok, you don't really HAVE to, but try to find someone to present with, or at least ask questions and be an interactive participant.)"