An Islamic State agent tried to persuade an undercover reporter to carry out an attack on London Bridge, a year before eight were killed and dozens injured at the landmark, it has been claimed.
A special report by BBC Inside Out London said one of its journalists was encouraged by the suspect to target London Bridge, suggesting he could do it alone or in a group.
The same agent also revealed explicit terrorist tutorials on the dark web, including step by step instructions on how to make a bomb, and a detailed description on how to create a fake suicide vest. They also contained illustrations showing how to attack a victim with a knife to inflict maximum damage.
The BBC said the details bore striking similarities to the attack on London Bridge on June 3, in which all three attackers Khuram Butt, 27, Rachid Redouane, 30, and Youssef Zaghba, 22, were shot and killed by police at the scene.
In a special report on Islamist-inspired extremism, researched over two years, the undercover journalist used Twitter to make contact with Birmingham-born jihadist and IS recruiter Junaid Hussain. Speaking through an encrypted messaging site, 21-year-old Hussain said he could help train the undercover reporter on how to make bombs from home.
When Hussain, from Birmingham, was killed by a US army drone in the Syrian city of Raqqa in 2015, another recruiter made contact with Inside Out's undercover reporter to continue the conversation. He detailed a plot to assassinate a police officer, including how to obtain firearms and bullets.
Inside Out London's undercover reporter said: "In July 2016, we discovered that the terrorist organisation was touting on Twitter and Facebook for British Muslims to stage attacks at specific London locations. We began conversing with one of their recruiters, who then invited us to chat privately on a secret messaging site. The authorities were fully aware of our contact with the terrorist organisation."
It came as a separate poll, conducted by Inside Out, found 90% of the 6,546 surveyed across England believe there will be more terror attacks. When asked whether they feel more or less safe in public spaces compared with 12 months ago, 29% of those surveyed said they feel less safe, and 10% think that they, a family member or a good friend could be killed or wounded in a terrorist attack.
More than half of those surveyed, 52%, believe the security services should be given more powers to tackle terrorism, even if that means individual privacy suffers.
:: Inside Out London will be broadcast on Monday at 7.30pm on BBC One