Those attackers didn't pick the right spot nor weapons like explosive that can maximise casualty. A good  template for that is The Oklahoma City bombing by  Tomothy McVeigh. They just wanted to create anti-muslim sensationalism and backlash by the general public and gov in order to radicalise further the UK muslims minority and to prepare for the coming World Jihad One

The limeys might be falling for that

http://www.standard.co.uk/news/crime/london-attack-theresa-may-declares-enough-is-enough-and-promises-new-era-in-fight-against-terorism-a3556436.html