From the depths of a shipment of scrap metal, a radioactive signal.
While false alerts can sometimes be triggered, this one was not one of them.
Metal bars embedded with uranium had made the 3,700-mile journey to London from Pakistan, via Muscat in Oman.
Had it not been intercepted by Border Force officials on Dec 29, the substance would have reached its intended recipient - an Iranian business with premises in the UK.
While false alerts can sometimes be triggered, this one was not one of them.
Metal bars embedded with uranium had made the 3,700-mile journey to London from Pakistan, via Muscat in Oman.
Had it not been intercepted by Border Force officials on Dec 29, the substance would have reached its intended recipient - an Iranian business with premises in the UK.