From Xie Yi- Our own correspondent in her first year here in the UK from China

I was late for class today. I didn't know the time, and I even didn't notice that it was time for class.. well, no excuse. I was then just wondering why there is no bell for class. It is my first time to realize this question.. My friend told me that in UK, bell is only used in some primary classes, but rarely in high school~well, is there any particular reasons for it? electronic saving? less noise?? In my opinion, the bell could help the students be more on time~