The Wood Green ricin plot was an alleged bioterrorism plot to attack the London Underground with ricin poison. The Metropolitan Police Service arrested six suspects on 5 January 2003, with one more arrested two days later.

Within two days, the Biological Weapon Identification Group at the Defence Science and Technology Laboratory in Porton Down were sure that there was no trace of ricin on any of the articles that were found. This fact was initially misreported to other government departments as well as to the public, who only became aware of this in 2005. Reporting restrictions were in place before the public's perceptions could be corrected.

The only subsequent conviction was of Kamel Bourgass, sentenced to 17 years imprisonment for conspiring "together with other persons unknown to commit public nuisance by the use of poisons and/or explosives to cause disruption, fear or injury" on the basis of five pages of his hand-written notes on how to make ricin, cyanide and botulinum. Bourgass had already been sentenced to life imprisonment for the murder of detective Stephen Oake, whom he stabbed to death during his arrest in Manchester. Bourgass also stabbed three other police officers in that incident; they all survived. All other suspects were either released without charge, acquitted, or had their trials abandoned. Bourgass had attended meetings of Al-Muhajiroun leading up to the plot.