“I have not seen this tactic in the UK before”
The trio wore leather belts attached to the vests, with three water bottles covered in tape attacked to them.
And the Met Police believe this could have been done to force a hostage situation.
“I have not seen this tactic in the UK before where terrorists create maximum fear by strapping fake explosives to themselves.
“Anyone who saw them on the night would have thought they were genuine.”
Cops have also released images of the haul of weapons found inside the van, including molotov cocktails.
The van was also found full of bags of gravel and chairs, which could have been to add weight to the van.
But, 27, tried to purchase a much larger van to cause maximum destruction in the capital, but his credit card was refused.
The warped killer and his two accomplices, Redoaune, 30, and Zaghba, 22, were shot dead by police who arrived at the scene in eight minutes.
Mr Haydon added that the killer’s vests were examined at the scene and found to be fake.