London Bridge attacker Khuram Butt was known to police and MI5 and this shows the chronic negligence of Britain's intelligence agencies.
That's according to Adam Deen, executive director of anti-extremism thinktank Quilliam, who said someone needs to be accountable for the failure to prevent Butt's attack on Saturday night.
Butt was one of three people who drove a van into pedestrians on London Bridge and attacked the neighbouring Borough Market. Security agencies have subsequently said he was known to them, but he was not under close surveillance as there was nothing to suggest he would conduct an attack.
Deen said the group with which Butt was affiliated, al-Muhajiroun, are open about supporting Islamic State and many members have been to Syria. He thinks security services believed Butt wouldn't commit an attack as he was so brazen in expressing his extremist views - a grave mistake.
The interviewee believes this failing has nothing to do with the intelligence agencies being overstretched, but was simply a case of negligence and cannot be excused.
Deen added that laws against terrorism are sufficient but aren't being used to the full extent, and a conversation about additional measures cannot be had until this is rectified.
Listen to the full interview above