From watching the television news reports of the Student Fees protest it was painfully obvious that the Millbank building had woefully poor security design. A small group of extremists and misguided broke away from the main body of the peaceful protest to attack the building containing the Conservative Party head quarters. I'll not comment on the Police preparedness, there are other people doing that already.
What particularly drew my attention was the cheap quality of glass walls at the ground floor reception area. Some of the glass had been treated with blast protection film, but the large windows, accessible at street level, were not made from laminated glass. It looks as though standard float plate glass had been used on the static windows and tempered glass on the doors.
Considering the risk created by the occupants (Tory Party) of the building the glass should have been replaced by glass strengthened by lamination to provide better security protection.
I also note the windows higher in the building appear to be plain sheet glass judging by the breakage patterns, not even any anti-blast film.
The layout of the reception area needs to be redesigned to prevent rush through attacks.