A civil servant has described for the first time how he fought off a terrorist on London Bridge with a narwhal tusk.
Darryn Frost, who works in the Ministry of Justice's communications department, has spoken about how he grabbed the artefact from the wall in Fishmongers' Hall as Usman Khan ran at members of the public with knives on 29 November.
Khan, armed with two knives and wearing a fake suicide vest, killed Saskia Jones, 23, and Jack Merritt, 25, in the attack during a prisoner rehabilitation programme.
Despite footage showing Mr Frost and other members of the public fending off Khan as they moved from the hall onto the bridge, the civil servant's identity has remained a mystery until now.
The 38-year-old South African, who has lived in the UK for 14 years, gave his account of the "horrible day" to urge people to unite against terrorism and raise money for the victims' families.
He said he was attending the event but ran to help when he heard a ruckus downstairs.
"When we heard the noise from the floor below, a few of us rushed to the scene," he told the PA news agency.
"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.
"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 said he passed the tusk to the other man before running back upstairs to find another to use.
When he came back down he found the first tusk "shattered across the floor" as people fled the building.
He said: "Along with others, I pursued the attacker, tusk in hand, on to 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."
Mr Frost offered his "sincere condolences" to the victims' families and friends, adding: "In reading about their lives and work I am convinced they represent all that is good in the world, and I will always feel the deep hurt of not being able to save them."
He revealed some of the injured refused treatment until others who were more seriously hurt were tended to first.
"That consideration and kindness filled me with hope on that dark day," he added.
Mr Frost said he was "eternally grateful" to the prisoners from the course and public who ran to help.
"Not only do I want to thank those who confronted the attacker, but also those who put themselves in danger to tend to the injured, relying on us to protect them while they cared for others.
"To the emergency services: you did yourselves and the country proud. I thank you too.
"To the public: I hope that the part I played in these terrible events can be used for good."
Mr Frost called on people to get behind a project he has launched called Extinguish Hate to "challenge hate and spread kindness".
He asked people to donate to the victims' fundraising pages - saskia-jones.muchloved.com and the "Celebration of the life of Jack Merritt" on GoFundMe.com
The civil servant said he had omitted "many details" of the incident "out of respect for the victims and their families" and because of the ongoing investigation and inquests into the attack.
Mr Merritt's funeral was held in Cambridge on Friday, while a memorial service for Ms Jones took place in Stratford-upon-Avon.