It has now emerged that one of the men was reported by
his friend to the authorities for his views and sharp decline into radicalism and nothing was done about it.
A friend of one of the suspected attackers says he had reported him to the anti-terror hotline, but no action was taken.
The man, who asked not to be named, told the BBC's Asian Network that the pair had spoken about previous attacks and he was shocked at what he had heard.
"We spoke about a particular attack that had happened and, like most radicals, he had a justification for anything, everything and anything," he said. "That day I realised that I need to contact the authorities."
But the friend claims the suspected attacker was not arrested and was allowed to keep his passport.
"I phoned the anti-terrorist hotline and spoke to the gentleman," he said. "I told him about our conversation and why I think he has been radicalised.
"I did my bit, but the authorities didn't do their bit."
The BBC has asked Scotland Yard for a response.
http://www.bbc.co.uk/news/live/uk-40147014
A shocking lapse in intelligence and follow ups. When the community reports someone it's obviously serious. The same happened with the Manchester attacker, and he was reported no less than five times.
@DesiGuy Oscar's post was a quite a while ago. I have also been clear I want such debate off this thread. Thanks.