Eyewitnesses told the Islamic Republic of Iran News Agency (IRNA) that the consular section staff who spotted the suspicious package immediately moved it out of the building as they informed the police.
The police cordoned off the nearby streets while bomb disposal experts were trying to defuse the device, but witnesses said the parcel blew up outside the building after several hours.
Those present at the scene also said the device was apparently a percussion bomb, which went off in an uncontrolled explosion. They said the blast did not leave any injury or damage.
This is while police said they carried out a controlled explosion on the suspect package, though it may not have contained any explosives.
The package was delivered on Friday to Iran's consular section, which is located in the west London Kensington district a few streets away from the Iranian embassy.
As usual I haven't been able to find this in any mainstream newspaper...