Horrible, but unsurprising, sadly.
This puts paid to Bush’s argument that we’re fighting in Iraq so we don’t have to fight here. If Al Quaeda can hit London, they can still hit in the US. The British have been doing better security for longer than we have. Among other things, London is covered with security cameras and police have historically had greater powers there.
Hopefully the security cameras will help catch the perpetrators, but they weren’t much help in preventing it.