The point that the two suspects in this horrific attack were known to the security services has been widely reported.
You would not expect me to comment on this while a criminal investigation is ongoing. But what I will say is this.
As is the normal practice in these cases the Independent Police Complaints Commission will be able to review the actions of the police and the intelligence and security committee able to do the same for the wider agencies.
Nothing should be done to get in the way of their absolutely vital work.