Three men accused of plotting a suicide bomb campaign bigger than 7/7 were secretly recorded saying their explosives would go off "boom", a jury heard today.
Irfan Naseer, Irfan Khalid and Ashik Ali discussed making explosives from household chemicals while under police surveillance last year, it was alleged.
The trio, all from Birmingham, estimated each device would killed around 25 people and maim dozens more if packed with steel nuts, Woolwich Crown Court was told.
Army explosives expert Captain Simon Wilkinson said their conversations showed "professional" understanding of how to make an improvised explosive device.
Naseer, Khalid and Ali deny preparing acts of terrorism in the UK and other terror offences. The trial continues.
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