A man has described how he fought off the London Bridge knifeman with a narwhal tusk before pinning him to the ground to help end the attack.
Darryn Frost, 38, was seen in pictures confronting Usman Khan, 28, who was armed with two knives.
The civil servant has spoken of his “deep hurt” at not being able to save Jack Merritt and Saskia Jones who were killed by Khan on 29 November.
Khan, who was wearing a fake suicide vest, was shot dead by police.
Mr Frost, who works in communications at the Ministry of Justice, told how he grabbed the narwhal tusk from the wall in Fishmongers’ Hall as Khan launched his attack during a prisoner rehabilitation event near London Bridge.
The South African-born Londoner then chased Khan onto the bridge, where footage captured him and fellow members of the public fending off the attacker.
Mr Frost, whose identity was unknown until now, can be seen pinning Khan to the ground before being pulled away by a police officer. The terrorist was shot dead moments later.
Khan was out on licence from prison when he killed Mr Merritt and Ms Jones and injured three others in the stabbing attack.
Speaking to the PA news agency, Mr Frost said he was attending the rehabilitation event with colleagues when he heard a commotion downstairs.
He said he then grabbed the decorative whale tusk, which had been hanging on a wall: “A few of us rushed to the scene. I took a narwhal tusk from the wall and used it to defend myself and others from the attacker.
“Another man was holding the attacker at bay with a wooden chair. I ran down the stairs, stood next to the man with the chair, and the two of us confronted the attacker.”
‘Knives raised above his head’
Mr Frost added: “He had knives in both hands and, upon seeing me with the narwhal tusk, pointed at his midriff.
“He turned and spoke to me, then indicated he had an explosive device around his waist. At this point, the man next to me threw his chair at the attacker, who then started running towards him with knives raised above his head.”
Mr Frost handed the tusk to the man next to him before heading back upstairs to find another one.
When he returned, he found the first tusk “shattered across the floor” and people fleeing the building.
He said: “Along with others, I pursued the attacker, tusk in hand, onto the bridge. We called out to warn the public of the danger and, after a struggle, managed to restrain him to the ground.
“At that point I was trying to isolate the blades by holding his wrists so that he could not hurt anyone or set off the device.”
In the footage of the altercation, Mr Frost can be seen grappling with Khan on the ground before being pulled away by an officer – seconds before police shot the attacker.
