Islamic State (IS) militants are said to have made a "dirty bomb" using radioactive uranium stolen from Iraq's Mosul University that could be "terribly destructive" if to go off in London.
According to the Mirror, Hamayun Tariq of Dudley, West Midlands was among those boasting about the bomb's development.
The device reportedly includes uranium from a stash of 40 kilograms looted by IS militants.
Iraq's UN Ambassador Mohamed Ali Alhakim had informed the UN Secretary-General Ban Ki-moon of the theft in July this year.
The militant group has also seized control of nuclear material from territories that the group controls.
