THE YARD--FOR IMMEDIATE RELEASE--
(Holmes Pub, Northumberland)-- Following photos by way of Telegraph via NY Times--
"The apparent detonator, which British law enforcement officials said was carried in the bomber's left hand, is also unusual for a manual detonator in a suicide device, in that it appears to have contained a small circuit board soldered inside one end," the American paper reported.
"It is not clear from the law enforcement images if the object was a simple plunger switch, or included a timer or a receiver that could be operated remotely via radio signal - or some combination."
Note no remnants of TNT stick wrappings which may indicate it was nothing more than a bag filled with gunpowder & shrapnel with a blasting cap attached to the detonator trigger.