"Clive George"  gurgled happily, sounding much
like they were saying:

>> Why? How does the speed limit affect what speed is _safe_ on any given
>> stretch of road?

> I can think of ways in which it would - mostly to do with how it affects
> the assumptions of other road users.

Given the standard of driving on our roads, don't you think any such 
"assumptions" are inherently dangerous?

Hell, it was drummed into my by my driving instructor that I ought to 
treat every other driver as an unpredictable loon - back in the '80s, and 
driving standards have only gone one way since then...