Having several times been underneath Concorde whilst on a boat, the "boom" is like someone firing two shots with a .22 rifle just behind your ear
Much as I love Concorde as a technical achievement, I can understand why they didn't let her go supersonic over land.
BTW, the development cost in today's money was only about twice what's just been spent on on Bush/Blair's adventure in Iraq so far - I know which I'd rather have my taxes spent on
