The verdict in the News of the World dirty bomb trial is not now expected until Monday at the earliest – 12 days after the jury retired.
The case followed an undercover investigation by News of the World journalist Mazher Mahmood.
Dominic Martins, 45, of Stanmore and Roque Fernandes, 44, and Abdurahman Kanyare, 53, both from Edgware, have denied conspiring to possess "a highly dangerous mercury-based substance" for the purposes of terrorism.
The jury retired on Wednesday, 12 July.
It is not the first time a Mahmood investigation has led to a high profile criminal prosecution.
In October 2002 information from Mahmood led police to arrest several men on suspicion of plotting to kidnap Victoria Beckham. Charges against the men were later dropped.